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rcunxne at any part of the earth's surface, and the megadyne is bout 1 -02 times the weight of a kilogramme.

The kilogram-metre is rather less than the erg-eight, being bout 9S million ergs.

The gramme-centimetre is rather less than the kilerg, being bout 9S0 ergs.

For exact comparison, the value of g (the acceleration of a >ody falling in vacuo) at the station considered, must of course >e known. In the above comparisons, it is taken as 980C.G.S. inits of acceleration.

One horse-power is about three quarters of an erg-ten per second. More nearly, it is 7 \}6 erg-nines per second, and one Kfnre de eheval is 7'36 erg-nines per second.

The mechanical equivalenl of one gramme-degree (centigrade) of heat is 41 6 megalergs or 41,600,000 ergs.

SCIENTIFIC SERIALS

I* the current number of the Quarterly Journal of Microscopic Scienei; Mr. E. T. Newton commences with a paper on he Structure of the Eye of the Lobster, his observation being the result of suggestions from Prof. Huxley. The structure of the eye is minutely discussed, and the accompanying illustrations are abundant. As a concluding remark, we read that "Notwithstanding all that has been written up to the present time concerning the mode of artion of the compound arthropod eye, we are still unable satisfactorily to solve this difficult physiological problem."—A paper by Prof. Betz, of Kieff, on the methods of investigating the structure of the central nervous system in Man, will be found of special interest, the hardening, cutting, and tinting of specimens being discussed.—M. Pasteur's new contributions to the theory of Fermentation, are translated from the "Comptes Rendus," and Prof. H. L. Smith's paper on Archebiosis and Heterogenesis, is reprinted from the lens.—A Resume, by Mr. W. Archer, of recent observations on Parasitic Alga;, is followed by Dr. Klein's Contributions to the Anatomy of Auerbach's Plexus in the Frog and Toad, and this by a valuable series of observations by Prof. Lister on the Natural History of Bacteria, in which a study of the life of Bacteria under different circumstances as regards the fluid in which they grow, shows that their general appearance, size, and shape depend in great measure on the fluid in which they are growing, their removal from one to another fluid causing them to take on quite a different form, and their replacement the reassumption of the original condition. Many important facts are to be learned from this paper. —Mr. E. R. Lankester describes in detail the microscopic and spectroscopic appearances of a new Peachcaloured Bacterium, named by him Bacterium rubescens. The colouring matter he names Becterio-rubrin. This Bacterium does not generally occur in isolated plastids, but generally forming films, encrustations, or tufts. Most are aggregated in adherent masses, several excellent drawings of which accompany the paper.

The Journal of the Franklin Institute, Sept. 1S73.—This number contains a useful paper by Mr. Hugo Bilgram, on the theory of steam governors.—In government reports on the decay and preservation of timber, Generals Cram and Gillmore recommend the Seely process as the best. It consists in subjecting the wood to a temperature above the boiling point of water, and below 300° Fahr. while immersed in a bath of creosote a sufficient length of time to expel the moisture. When the water is thus expelled the pores contain only steam ; the hot oil is then quickly replaced by a bath of cold oil, by means of which change the steam in the pores of the wood is condensed, and a vacuum formed into which the oil is forced by atmospheric pressure and capillary attraction. Gen. GiUmore thinks a wooden platform, thoroughly creosoted, would last twenty to thirty years, and be better than a stone platform during that entire period.—An important paper by Prof. Thurston (extracted from the Iron Age), treats of the molecular changes produced in iron by variations of temperature.—Mr. Mott points out the conditions of good construction in lightning rods, and Dr. Feuchtwanger gives some information as to nickel and its uses in the arts, coinage, and nickel plating.—An oil discovery of unusually rich character is announced from the neighbourhood of Tiluirille, Pa. ; the production of the new region being estimated at 30,000 barrels per day.

Dtr Haturfrrscher, September 1873.—We note, in this num

ber, two striking observations in animal physiology. One of these refers to the torpedo, which has been a puzzle to physiologists, inasmuch as, while giving shocks strong enough to lame or kill another animal, its own muscles do not show the least contraction. Du Bois Reymond's hypothesis is, that while the stimulation to discharge goes forth from the central organ, the same organ sends out at the same time a counteractive influence through the nervous system, which neutralises the excitability of the nerves. M. Frani Boll took a recent opportunity of experimenting with the fish on the Italian coast, and, among other things, he tested this theory by cutting some nerves, and watching their muscles when he stimulated the electric nerves. The neutralising stimulation being thus cut off, the muscles should, he thought, contract, if the hyphothesis were true; and they did so, the muscles of the unsevered nerves remaining at rest. Still, he hardly thinks the experiment decisive, because nerves are more excitable after section.—The other observation is by Prof. Fick, who has found, by manometric measurement, a less pressure of blood in the left ventricle than in the aorta; 80 mm. of mercury in the one case, 104 to 128 in the other (in a dog). He supposes the blood, only partially filling'.the ventricle, at the apex, to be shot against the semilunar valves, forcing them open by its vis :m In the neighbourhood of the valves the pressure must quickly rise. In short, as the author puts it, the blood is not pressed, but hurled (geschleudert) into the aorta.—There is a useful abstract of the chief points in a paper by Prof. Abbe (to Schuhe's Arc/iiz') on the capability of the microscope and its limits. He seeks to show, by physical deductions, that the limit of magnification is as good as reached, in our best systems. Some curious observations by M. van Tieghem are given in a note on the independence of the individual organs of the embryo of plants.—M. Ebermayer, we find, has been examining the influence of forests on ozone-contents of the air; he states there is more ozone in and near forests than in the open, but among the denser branches there is somewhat less than in the open closely bordering the forest; and in the tops of the trees there is more than in the lower parts.—Several French Academy notes are abstracted: on the magnetic force of annealed steel, on development of electricity in liquid mixtures, on the planet Mars, &c. ; also Royal Society papers. Some meteorological observations as to distribution of heat in Switzerland deserve notice.

Bulletin Afensuel Je la Societi" d'Acclimatation de Paris. August.—In a paper on the "Causes of the Depopulation of our Rivers," M. C. R. Wattel enters at length into the question of the French river fisheries, which will be read with interest by fish-culturists. Some interesting information as to the effect of navigation and trade on the rivers is given; but the great danger to the fisheries lies in the unrestricted destruction of immature breeding-fish: and M. Wattel recommends that steps should be taken to prevent over-fishing and to facilitate the erection of fishways on the rivers.—The notes of Dr. P. Mares on the acclimatisation of various sorts of Eucalyptus in Algeria, are interesting.—The results of the experiments to produce different coloured silks go to show that silkworms fed on cherry-leaf produce a bright chromo-yellowcoloured silk, those on pear-leaves a darker shade of the same colour, those on apple-leave* a nearly white silk, but coarser than that of the silk-worms fed on mulberry-leaves.—An extract is given of a work by M. E. Ferris, on "Birds and Insects," in which he considers the advisability of protecting small birds. M. Perris, granting all the birds are insectivorous, either continually or occasionally, acknowledges the good they may do, but doubts whether a large proportion of the insects destroyed are hurtful to man; and he raises the question whether, therefore, it is desirable to protect birds to kill what would otherwise do no harm.

The September number commences with a paper by the Secretary on some Australian vegetables, the introduction of which into Algeria is proposed.—An interesting paper on the breeding of ostriches in captivity is contributed by Capt. Crepu, who has kept several pairs of these birds. I lis observations throw much light on the natural history of the ostrich. M. Comber describes the mortality which has seized the deer and other animals in King Victor Emmanuel's park at La Mandria. The calamity is a' tributed partly to over-crowding and partly to the want of shelter and proper protection. In 1S65, when the park and grounds were carefully cultivated, 13 deaths occurred. In 1873, the park being left in its natural state, 172 deaths are I recorded.—An important paper on the production of milk is the result of a conference at the Jardin d'Acclimatation in July, and appears opportunely at the present moment, when the subject is attracting so much public attention. —M. E. Perris continues his remarks on "Birds and Insects."

SOCIETIES AND ACADEMIES Manchester Literary and Philosophical Society, October 7.—E. W. Binney, vice-president, in the chair.—" Atmospheric Refraction and the last rays of the Setting Sun," by Mr. D. Winstanley. It is recorded in the Proceedings of this Society that a letter dated from Southport and written by Dr. Joule was read at the meeting held on the 5th October, 1869. In that letter it is remarked that "Mr. Baxendell noticed the fact that at the moment of the departure of the sun below the horizon the last glimpse is coloured bluish green." Dr. Joule also observes that on two or thrre occasions he had himself noticed the phenomenon in qui- .ion, and that "just at the upper edge where bands of the sun's disc are separated one after the other by refraction, each band becomes coloured blue just before it vanishes." During the past eighteen months the writer, from his residence in Blackpool, has had frequent opportunities of observing the setting sun, and has noticed the phenomenon of the final coloured ray certainly more than fifty times. To the naked eye its appearance has generally been that of a green spark of large size and great intensity, very similar to one of the effects seen when the sun shines upon a well-cut diamond. The colour, however, is by no means constant, being often, as in the case of Mr. Baxendell's observation, bluish green, and at times, as mentioned by Dr. Joule, quite blue. The period of its duration, too, is likewise variable. Sometimes it lasts but half a second, ordinarily perhaps a second and a quarter, and occasionally as much as two seconds and a half. When examined with the assistance of a telescope, it becomes evident that the green ray results at a certain stage of the solar obscuration, for it begins at the points or cusps of the visible segment of the sun, and when the "setting " is nearly complete, extends from both cusps to the central space between, where it produces the momentary and intense spark of coloured light visible to the unaided eye. From the fact of the gieen cusps being rounded I apprehend that irradiation contributes to the apparent magnitude of what is seen. The range of colour too as seen in the telescope is more varied, and the duration of the whole phenomenon more extended, than when the observation is made only with the naked eye. Respecting the increased range of colours seen when the phenomenon is observed with telescopic aid, I may mention that on the 28th of June the sea was calm and the sky quite cloudless at the setting of the sun. Of the final coloured rays fiftfen diameters showed the first to be a full and splendid yellow, which was speedily followed by the usual green, and then for a second and a half by a full and perfect blue. Respecting the increased duration of the colour, I have found that when the atmosphere is sufficiently favourable to allow a power of sixty diameters being employed with a three-inch object-glass, the green effect is seen at that part of the sun's limb in contact with the horizon even when one half the sun is still unset, and of course from then till final disappearance. The different colours seen, together with the order of their appearance, are suggestive of the prismatic action of the atmosphere as the cause of their production, and the interception of the horizon or the cloud as the cause of their separation. Assuming the correctness of this view, it becomes evident that an artificial horizon would prove equally efficacious in separating the coloured bands, and also that if employed during an inspection of the sun's lower limb, the least refrangible end of the spectrum would be disclosed. By projecting a large image of the tun into a darkened room I was enabled to get the whole of the spectrum produced by the prismatic action of the atmosphere in a very satisfactory manner. In this case a semicircular diaphram was used, so placed that its straight edge divided the field of view into equal parts, from one of which it obscured the light. The diaphram was placed in the focus of the eyepiece, and by rotating it every portion of the sun's limb could be in turn examined, and that too in the centre of the field, so as to be equally subjected to the minimum of the peculiarities of the instrument. When the sun's lower limb was allowed to descend into the field of view the first rays were intensely red. After a momentary duration they gave place in succession to orange, yellow, and green, which were then lost

in the ordinary refulgence of the sun. The upper limb gin green, blue, and finally purple, which latter colour I have rhs far never seen upon the natural horizon. I apprehend that the results here given sufficiently prove that atmospheric refraction 1 the cause of the coloured rays seen at the moment of the ta'i departure below the horizon.

Cambridge Philosophical Society, Oct 20.—The foliaring communications were made to the Society :—By Mr. J. C. W Ellis, Sydney College: Mechanical means for obtaining the rei roots of algebraical equations. — By Mr. A. Marshall, St- John'; Graphic representation by aid of a series of hyperbolas of sore economic problems having reference to monopolies.—By Mr. H H. Cunyngame. St. Johns : A machine for constructing a sens of rectangular hyperbolas with the same asymptotes, Paris

Academy of Sciences, October 27.—M. de Quatrtbgo, president, in the chair.—The following papers were read ;— Sixth note on guano, by M. ChevreuL—Answer to Respighi'i note on the magnitude and variation of the sun's diameter, it Father SecchL The author defended his method from Resptgbu criticisms as regards the effect of heat in distorting the im^! during the passage through the prisms. He found that the effect a heat on compound prisms was very considerable, and theretxr used his object-glass prism ; and stated that in a future letter it intended to show that there were true variations in the sots diameter.—On crystalline dissociation, by MM. Favre xod Vakon. The authors continued the account of their itsearches, the present portion of the paper dealing with ths valuation of the work done in the various solutions.—Note tct the tertiary supra-nummulitic formation of the Carcassonc basis, by M. Leymerie.—On certain cases of human double monstrocity, by M. Roulin.—Note on the origin and method of development of omphalosic monsteis, by M. C Dareste.— New method of condensing liquifiable substances held in suspension by gases, a reply to M. Colladon, by M M. E. Pelouie ani P. Audouin.—M. Guerin-Meiieville sent a letter in which he asserted that the Phylloxera is not the cause, but a consequence of the vine disease.—Note on the swellings produced on vine rootlets by the Phylloxera, by M. Max. Cornu.—Results of aperiments on the destruction of the Phylloxera by means of carbonic disulphide, by M. Bazille. The author found that tim agent was very successful, and that the doses could be reduced considerably but that different sous require different closes.—Oa the action of the condenser on induction currents, by M. Lecocq de Boisbaudran.—On the purification of hydrogen, by M. Ch. Viollette.—On the Cape diamond fields, by M. Hugon—On the sugar contained in vine-leaves, by M. A. Petit. The auih'Jf found in I kilo of leaves as much as 33 grammes of cane --ugar and 12 of glucose ; this was, however, exceptional, the latter generally exceeding the former and the total quantity of both being less.—On the Rhizocephalous Cirripeiles, by M. A. Giard.— On the irritability of stamens, by M. E. Meckel. The author has distinguished two orders of movement in these organs.

CONTENTS Pm

The Government And Our National Museums 1

Bain's Review Of " Darwin On Expression" 1

Lahore To Yarkand . j

Our Book Shelf 4

Letters To The Editor:

Prof. Young and the Presence of Ruthenium in the Chromosphere.

—Prof. H. E. Roscoe, F.R.S 5

The Miller- Caszlla Thermometer.—P. Pastorslli ..... *

Captain Hutton's "Rallus Modestus."—Dr. Walter L Bulloe =

Flight of Birds.—Prof. Ioseph Le Conte 5

Collective InstincL—George J. Romanes; Dr. A. Paladilhe . s

Venomous Caterpillars.—R. Riclachlan, F.L.S e

Harmonic Echoes.—Arnulph Mallock $

Evolution as applied to the Chemical Elements.—C.T. Blansharc G

Ancient Balances.—G. F. Rodwell, F.C.S $

Brilliant Meteors.—John Curry t THURSDAY, NOVEMBER 13, 1873

Sir Henrv Holland K

The American Museum Of Natural History In Central Park.

New York. By Albert L. Bickmorb, Ph.D >t

The Common Froc, III By St. George Mivart. F.R.S. (jpms*

Illustrations) ...*.,.« to

A Fossil Sirenian From The Red Crag Of Suffolk 13

On The Stick-fish {Osttoerlla septentrionalis) And On The Habits

Of Sea-pens. By Dr. J. E. Gray. F.R.S ij

The Relation Of Man To The Ice-sheet In Thr North Of

England. By R. H. Tiddbmann, F.G.S Sa

Atlantic Fauna. By Frou. P. Johnson . . Js

Notes 16

The Selection And Nomenclature Of Dynamical And ElecTrical Units 18

Scientific Skrials c?

Societies And Academies ja

ON THE MEDICAL CURRICULUM I N a recent number of this journal (nature, Oct. 2, -■- 1873) we made some remarks on medical studies, which were intended more for students themselves than in any way to bear on the principles of medical education. To the latter subject special attention has just been directed by Prof. Huxley, who, as Lord Rector of the ■University of Aberdeen, has drawn up a series of propositions for the consideration of the Court at the next meeting in February or March, on which occasion he will deliver his inaugural address.

The following are the motions that the Lord Rector will propose :—

"I. That, in view of the amount and diversity of the knowledge which must be acquired by the student who aspires to become a properly qualified graduate in medicine; of the need recognised by all earnest teachers and students for the devotion of much time to practical discipline in the sciences of chemistry, anatomy, physiology, therapeutics, and pathology, which constitute the foundation of all rational medical practice; and of the relatively short period over which the medical curriculum extends—it is desirable to relieve that curriculum of everything which does not directly tend to prepare the student for the discharge of those highly responsible duties, his fitness for the performance of which is certified to the public by the diploma granted by the University.

"II. That it would be of great service to the student of medicine to have obtained, in the course of his preliminary education, a practical acquaintance with the methods and leading facts of the sciences comprehended by botany and natural history in the medical curriculum; but that, as the medical curriculum is at present arranged, the attendance of lectures upon, and the passing of examinations in, these subjects occupy time and energy which he has no right to withdraw from work which tends more directly to his proficiency in medicine.

"III. That it is desirable to revoke or alter ordinance No. 16, in so far as it requires a candidate for a degree in medicine to pass an examination in botany and zoology as part of the professional examination ; and to provide, in lieu thereof, that the examination on these subjects shall, as far as possible, take place before the candidate has entered upon his medical curriculum.

"IV. That it is desirable to revoke or alter said ordinance No. 16, in so far as it requires candidates for the degree of doctor of medicine to have passed an examination in Greek, and that, in lieu thereof, either German or French be made a compulsory subject of examination for said degree, GTeek remaining as one of the optional subjects."

In considering these points a review of the method by which the present position of the medical curriculum has been arrived at, will throw considerable light on the steps which ought to be taken for its improvement, and will show how subjects which have but an indirect bearing, or none at all, on medicine proper have been gradually made to form an element of the course of study, without any question having been asked as to whether their introduction does not bring its concomitant disadvantages.

The influence of Materia Medica seems to have been

great in bringing about the present state of affairs. When

Dr. Anthony Todd Thomson and Dr. Pereira, in their

enthusiasm for their favourite subject, extended its limits

Vol. Ix.—No. 211

so as to include a full account of the source and history of every one of the articles which were mentioned in the Pharmacopoeia, and went so far as to give a full description of Gallus bankiva, together with all the steps in the development of its egg, simply because Ovi vitellus is an antidote against poisoning by corrosive sublimate, and is employed in the preparation of Mistura Spiritus Vini Gallici (egg flip), it is evident that as the sciences of zoology and botany became more profound, Materia Medica as a subject would proportionately expand. At last a time came when separate lectures had to be given on the above-mentioned kindred subjects, in order that those on Materia Medica might be more easily comprehended by the student; and, as might be expected, these independent lectures on zoology and botany, as those on chemistry had done before, became so complete in themselves, as to reduce the subject which had given rise to their introduction, to a simple formulary for the chemist, with references to the sources of the necessary scientific information. The introduction, however, of zoology and botany as separate independent elements of the curriculum, brought into the medical education a large ma ss of matter, which is very valuable no doubt in itself, but to the student entirely irrelevant; and as in the short pupilage of three or four years there is a much larger amount that ought to be learned than can be-properly acquired in the time, it becomes a matter worth serious consideration, whether subjects which are not indispensable to a thorough training should be still taught and be required by the examining bodies. The question therefore resolves itself into the determination of whether the loss of time necessary for obtaining a superficial knowledge of a couple of sciences, is counteracted by the advantages of those sciences as a mental training and a basis for higher work? In an Introductory Lecture delivered some time ago at University College, Prof. Huxley throws the weight of his opinion in the scale against retaining the subjects which must be to him most dear, in the medical curriculum; and most will agree with him, notwithstanding the many difficulties in the way of an improved programme.

With regard to Prof. Huxley's fourth proposition, in which it is considered desirable to omit Greek from the preliminary examination, and substitute German or French in its place, the interest will not be so great to most, as that relating to the scientific qualifications that are necessary. The same conservative spirit which has prevented any reduction in'the overloaded Biological portion of the curriculum, has, without question]of any kind being asked, never even hinted at any^change in the long-established and well-tried school-course, in which the at one time practically valuable and indispensable Greek and Latin are still retained, though of less importance at the present day. How many of our scientific men find that nothing deters them in every step of their work, more than a want of knowledge of the German language, now that the scientific activity of that country is so considerable and so rapidly increasing. There must be a change with the times, even in primary education, and we hardly think that in his introductory address to the King's College Medical Society on the 23rd of last month, Prof. Curnow put the case fairly when he disapproved of the substitution of German for Greek, because the one could be

c

mastered by a few months' residence in a neighbouring country, whilst the other had done more to develop true culture than almost all other writings since. It is not proposed simply to substitute German or French for Greek, the advantages to be derived from which are now fully absorbed into the spirit of the nation, but, by the change, to leave a sufficient time, in addition to the education in modern languages, for the study of the Natural Sciences during the school-boy period. That the dead languages form an excellent mental training no one doubts, but that Physics and Chemistry do the same is daily becoming more certain; and the time is not far hence when the facts and methods of Physiology and Comparative Anatomy will be so well known and assorted, that they may be placed in the same category.

THE SOUTHERN UPLANDS OF SCOTLAND*

THE range of hills, which in Scotland extends from the German Ocean to the Irish Sea, having a N.E. and S.W. direction, has been aptly designated the Southern Uplands. This range is nearly parallel in its course to that of the Highlands proper. It exhibits hills, some of which attain to an elevation approaching nearly 3,000 feet; but its physical features, although marked in many localities with scenes of great beauty, are devoid of the stern and rugged grandeur which characterises the more northerly mountains of Scotland. The hills of this range usually consist of rounded and grass-covered undulations, or long tracts of plateaux. They have been specially named the "pastoral district of Scotland," and their scenes have furnished subjects for many a pastoral song, and many a border ballad.

The Southern Uplands of Scotland are cut deeply into by some of the streams which flow into the Solway Firth, theEsk, the Annan, the Nith, the Urr, and the Dee being the most important of them. They are drained on the southward side by the Cree and the Luce ; on the northward side they are the sources of the Ayr; and the Tweed and its tributaries drain a large'portion of their north-east area.

In the early period of Scotch geology, the days of Playfair and Hutton, the Southern Uplands were regarded as affording no traces of the evidence of life in the rocks which compose them; and these rocks were referred to the "primary" group. It was not until the discovery of^fossils in a limestone which occurs at Wrea in Peeblesshire, in their higher portion, by Sir James Hall, that the rocks which formed these hills were assigned to the "transition " age. The terms " primary" and " transition" have now ceased to be applicable to the nomenclature of geology; and the discovery by Prof. James Nicol in 1840, in the flaggy beds of Greiston in Peeblesshire, of graptolites, indicated the Silurian age of the strata here. Since the discovery of Nicol, several geologists have added greatly to our knowledge of the rocks which compose the Southern Uplands. Other bands of graptolites have been found richer in fossil contents than those first discovered; and these, along with a few other forms of organic remains, have still further confirmed the Silurian age of the

* Memoirs of the Geological Survey of Scotland, Sheets 1, 2,3 and 15, &c. Explanations of, 1871, 1872, 1873,

great mass of strata which make up the hilly country i the South of Scotland.

The result of the observations made on the rocks c the Southern Uplands up to the period when they car-under the notice of the Geological Survey of Scotland i-i to the conclusion that the lowest strata exhibited »treferable to the Llandeilo age. That these l.landeilo roe'e were succeeded by deposits containing fossils, as in ti. case of the Wrea limestone, indicating the horiion r the Bala or Caradoc rocks, was also kno'vn — 2certain rocks which occur near the north-western marji: of the area in the neighbourhood of Girvan in Ayrshire. have been referred by Sir Roderick Murchison to a. s-tiL higher position in the Silurian series.

The labours of the Geological Survey of Scotland havc not only confirmed these conclusions, but have addx greatly to our knowledge of the nature of the Silun^: rocks of the South of Scotland. They have; also furnished subdivisions of these rocks, and a more ample account of their arrangement and fossil contents.

Every geologist familiar with the lower portions of it: Silurian rocks of the Southern Uplands, the Llaadeib strata, had experienced great difficulty in recognisiii; horizons, in this series, such as would enable him ta divide these rocks into distinct portions. It is true that bands of anthracitic shale abounding in graptolites were, as regards their petrological nature, very distinct froir: the rocks in which they were intercalated. The great mass, however, of the Llandeilo beds of the Southern Uplands consist of rocks known in old petrological nomenclature as "greywackes "—-a name which is still retained for want of a better—and as these rocks differed only in coarseness, and sometimes in colour, this circumstance rendered the division of the South of Scotland Silurian rocks into separate groups extremely difficult. And when it is added to this that contortions have greatly folded and denudations have largely planed oft" the edges of these rocks, the difficulty of making out distinct horizons among the Llandeilo strata of the South of Scotland becomes very apparent. It is only by a careful, continuous, and long series of observations recorded in maps large enough to show all the contortions, the ins and outs of the strata, that these rocks could be brought into subdivisions enabling them to be recognised. Such | have been the work of the officers of the Geological Survey of Scotland ; and now we have in the explanatory notes to some of the sheets which have been published, the results of their work recorded, and the subdivision of these Llandeilo rocks indicated.

The explanation to Sheet 15, published in 1871, which includes, among other matters, a description of the Llandeilo rocks occurring in that portion of the Southern Uplands occupied by the north-west part of Dumfriesshire, the south-west portion of Lanarkshire, and the south-east portion of Ayrshire, contains the results of the labours of the Survey among these rocks. There do not appear, in any portion of the South of Scotland Silurian strata, any rocks which appertain to an age older than the Llandeilo; and these Llandeilo rocks are referable only to the Upper Llandeilo series, the Lower Llandeilo or Shelve rocks of Murchison, the Arenig rocks or Skiddaw slates of Sedgwick, being unknown in the district This Upper Llandeilo series exhibits itself in the form of an anticlinal axis near the southern border of the Silurian area. This axis can be well seen in Roxburghshire and Dumfriesshire, having a north-east and southwest direction. It has also been recognised by the officers of the Geological Survey in Wigtonshire ; and the rocks which it exhibits, which are the lowest in the Southern Uplands, have been designated by Prof. Geikie the "Ardwell group." This group is made up of "hard, •well-bedded greywackes and grits, with bands of hard shale or slate. These rocks have a prevailing reddish or brownish hue, especially on weathered surfaces."

As seen in Dumfriesshire and Roxburghshire these low rocks have the same aspect and nature. They have afforded, both in Wigtonshire and Dumfriesshire, markings which have considerable resemblance to the fossil described by McCoy as Protovirgularia, and in Roxburghshire they have yielded crustacean tracks, but no other traces of organic remains have been obtained from them. Above the Ardwell group the officers of the Geological Survey recognise a mass of strata to which they have j;iven the name of the "Lower or Moffat Shale group." This group is-composed of '•' flaggy greywacke and grey shales," which are distinguished by the occurrence in them of several bands of black carbonaceous shales. These strata are well developed in the neighbourhood of Moffat, Dumfriesshire, from whence they derive their name. The black carbonaceous shales are very persistent, having been traced by the officers of the Survey from near Melrose to the western shores of Wigtonshire, "a distance of more than 100 miles." Three bands of carbonaceous shales can frequently be made out, but occasionally they come together so as to form one thick band. These bands are very prolific in graptolites. They have, from their carbonaceous aspect, induced many persons, under the guidance of "practical miners," to expend large sums of money in search after coal, and some of the spots where they have been worked are known under the name of " coal heughs."

Although the Moffat group is well developed through the greater portion of the Southern Uplands, it is on the coast of Wigtonshire that the best sections of the series can be seen. Here they, are recognised resting on the Ardwell group, having at their base "grey and reddish shales, and clays, with calcareous bands and nodules, and enclosed bands of black shale, the lowest members being hard and flaggy." The second member of the Moffat group, as seen on the Wigtonshire coast, consists of black shales with intercalated clays, like the fire-clays of the coal-measures. Calcareous nodules and lenticular bands are also associated with the black shales, the whole being so intensely plicated as to render an attempt to determine their thickness extremely difficult. Upon the black shales well-bedded greywacke and grits occur with occasional shaly partings. These are succeeded by black shales so much jumbled and jointed, that their thickness cannot be made out. The next sequence consists of grey flagstones, flaggy sandstones, and grits, in beds of varying thickness up to 3 or 4 ft., with abundant partings of grey shale. To these succeed a thick band of finely laminated grey shale, 3or4ft Black shales, bands 12 to 18ft. in thickness, occur next, and the highest members of the group consist of fissile sha'es.

The Moffat group, as represented in Wigtonshire, has a thickness of about 1,000 ft., of which more than half consists of flaggy greywacke beds. The underlying series, the Ardwell group, probably attains to a much greater thickness.

The third member of the Upper Llandeilo rocks of the Southern Uplands of Scotland, like the second, derives its name from Dumfriesshire. It is well exhibited in the hill called Queensberry, and has been designated the Queensberry grit group. The characters of this third member, as they are seen in Wigtonshire, "consist of greywacke and grits in massive courses, with occasional bands of grey and greenish shales." Massiveness and regularity of bedding and jointing are the characters of this group. The sandstones are often coarse; and sometimes even coarse conglomerates appear, in'which some of the embedded fragments are sometimes from 2 ft. to 3 ft. in diameter, a feature which distinguishes the Queensberry group from all the other members of the Upper Llandeilo rocks of the South of Scotland. Fossils appear to be absent from this group, no trace of them having been met with in the three parallel bands which traverse Wigtonshire.

In the Dumfriesshire portion of the Upper Llandeilo area of the South of Scotland, there have been recognised, above the Queensberry grit group, black shales with graptolites, the thickness of which have not yet been ascertained. To these black shales the name of Hartfell group has been given. As the typical area where these rocks occur is in the higher part of the Annandale district, the sheets of which have not yet been published, we have at present no account of this group from the Geological Survey.

The Hartfell group is succeeded by the Daer group, which is made up of hard blue and purplish greywacke, and grey shales. It derives its name from a stream flowing from the north side of Queensberry into the Clyde. Its strata are greatly folded, and no reliable estimate can be formed of the thickness of the Daer group.

The Hartfell shales of the Daer group seem to thin out towards the south-west. They have not been distinctly recognised in Wigtonshire, where the Dalvcen group, which in Dumfriesshire succeeds the Daer group, is seen resting conformably upon the Queensberry grits.

In Dumfriesshire the Dalveen group consists of fine blue and grey greywacke, and shales having no features distinguishing them from other members of the upper Llandeilo rocks. Their estimated thickness is about 2,900 ft. They are well exposed in Dalveen Pass, Dumfriesshire, whence their name, and in Dinabid Linn they are seen passing under a coarse pebbly rock, "Haggis Rock."

In Wigtonshire the lower part of the Dalveen group is seen overlying the Oueensberry rocks south of Corsewell Lighthouse. Here its lower portion is remarkably shaly, but thick masses of greywacke also occur. Among the shaley beds are some bands worked at Cairn Ryan for slates. These slates have long been known as affording graptolites; and another thin band of black shale also containing the same fossils appears in this group in Wigtonshire.

In Dumfriesshire above the Dalveen group a series of

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