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As the teeth of Ptychodus are so well known to of a single mouth), in which all the forms may be all acquainted with the fossils of the Chalk, it is easily recognised as modifications of a single type. unnecessary to describe their general shape in detail About ten species occur in the English Chalk, and of here, and reference need only be made to their | these the commonest are P. decurrens, P. polygyrus;

and P. mammillaris. The first has the central part | British Museum. To whichever jaw this dental of the tooth not much raised, with the transverse armature belonged, its arrangement is obviously very ridges all insensibly merging into the surrounding different from that of Cestracion, and if we were now granulated area; in the second (fig. 82), the trans- venturing upon innovations, instead of simply verse ridges and furrows are coarser and mostly bend recording the present state of this branch of Palæontoround on reaching the granulated area, producing logy, we should remove Ptychodus altogether from gyrations suggestive of the specific name; in the the Cestraciont family, and endeavour to find a place third (fig. 81), the central part of the tooth is raised for it in proximity to some of the Rays.

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into a more or less prominent dome, and the One other extinct genus is usually referred to the surrounding granulated area is characterised by the Cestraciontidæ,- Plethodus from the English Chalk. delicacy of the markings, and the frequent presence | It is founded upon detached dental plates, which are of radiating grooves.

flat, and of somewhat irregular outline, with a With regard to the disposition of the teeth in the punctated grinding surface. mouth, very little as yet has been ascertained, owing

(To be continued.). to the fragmentary nature of most of the fossils ; so much is known, however, as is represented in the "ENGINEERING” mentions weather vanes illudiagrammatic plan (fig. 83), which embodies the minated by electricity, and a trial suggested with information afforded by specimens exhibited in the l one twenty feet long, with a light at either end.

of light cannot pass unnoticed, and the delightsome MY GARDEN PETS.

hum which expresses his happiness, as he circles and

shoots to and fro, when the cloud-dispelling sun By E. H, ROBERTSON.

cheers him into activity, is pleasant indeed to him Parr II.

who loves such rural sounds. Ilis pathetic cry of C PRING-TIME is particularly disastrous to my

distress, too, when unable to extricate himself from U pets. Tempted by the bright sunshine they

the cruel grip of a spider, or has been accidentally roam to distant pastures, to provide for the wants

squeezed beneath some weight, calls for the ready of a daily increasing family. After a night's rest

| help of him whose ear is alive to the cry of pain. and refreshment, they issue forth full of energy,

This diversity of cries alone should teach the novice and without impedimenta, but return later in the

when to avoid proximity to bees' quarters ; but as day tired and heavily laden, to be cut down on

there is an art in seeing, so is there in hearing, and the very threshold of home, by the cruel, biting

some there are who never learn, and if they have wind, thousands of the weary labourers being thus

anything to do with bees they soon pay the penalty sometimes lost. To a lover of Lees it is dis

| of their ignorance. tressing to see the ground strewn with their chilled Dear reader, have you ever witnessed the contortions carcases, and, as I never pass a chilled bee without

l of a terror-stricken bee observer? If not I can promaking an effort to warm him into life, I gather mine mise you an entertaining sigli, and even if you be an into a bell glass, which, inverted over a stand, I

unfortunate wight upon whose liver that most baleful place before a fire. I may have collected but a score, of all subtle malignancies-the east wind-has laid perhaps it contains 500 or 600. Soon the inert mass

its firmest hold, it will most assuredly provoke your shows signs of vitality-here and there a tiny leg or mirth. It always reminds me of the mechanical antenna quivers, a silvery wing shimmers in the figures which the cockney void of taste erects upon a flickering firelight, a few moments later and sundry | post or staff in his small garden. The figure gyrates pollen-laden little fellows may be seen brushing their | upon a pivot, and every breath of wind sets in rapid coats and wings, and loudly buzzing, as they scamper motion, windmill fashion, two fin-like appendages, up and down the side of their prison, in search of that are supposed, by a wide stretch of the imaginasome means of escape, and soon nearly all are astir. | tion, to resemble arms. See but the terrified one as Turning the glass mouth upwards in the open air, the | he wildly smites the air in his futile efforts to beat thoroughly resuscitated fly off to their hives, a few down his puny foe, and the inanimate figure will not yet fully recovered, after a short fight, descend present itself to the mind's eye. His ludicrous antics ing to the ground, to be returned to the glass, re can have but one effect. The bee, perfectly innocent warmed, and fed with honey until fully restored. of mischief, naturally enough believes itself to be the Sometimes every bee may thus be brought back to l object of unprovoked attack, and, resentíul, makes life, but more frequently a small proportion (say short work of his enemy, and if the latter escape scot from five to twenty per cent.) are not to be so easily free his escape is due either to the thickness of his restored ; they are almost invariably the old and worn garments, or, more probably, to the hastiness of his out. quickly recognised by their black, hairless retreat. It may be stated that, as a rule, bees never bodies, whose slender thread of life has been severed | sting when roaming, nor even close to their homes, by the north wind's keen edge. If apparently drowned unless irritated by the recent plunder of their store, bees be placed upon a blotting pad, and thus treated, or disturbed by the passing and repassing of any the genial warmth will almost certainly revive

I person in front of their hives. them.

Perhaps there is nothing that more readily excites To a person not familiar with bees the statement a bee to anger than the latter. The term vicious, so that the sounds emitted by them are as varied, and often applied to bees and wasps by the ignorant, is a as expressive of fear, anger, pain, &c., as are those of senseless misnomer, and although there is probably human and other animals, may seem incredible ; it is, as great a diversity of disposition to be found in any nevertheless, strictly and literally true, and the ear one bee community as amongst the individuals of of the experienced apiarian, or observant naturalist, other races, they are most certainly not aggressive, soon learns to distinguish them. There is not a and the notion that they sting of malice prepouse is greater difference between the soft purr of the con an absurd one. Even a stranger may, with impunity, tented puss, and her threatening growl when tearing stand before a hive when bees are returning home her prey, her pleading “mew," and her diabolic heavily laden, and although his garments may be caterwauling, or unearthly sleep-disturbing yell, than thickly studded with the weary little labourers, not there is between the droning hum of the tired | one will molest him, nay, if the tip of the finger be homing bee, and the fierce threatening buzz which presented, the tired insect will almost invariably warns the intruder to decamp.

accept the proffered aid. Let the stranger, however, The crisp whirr with which the active little fellow beware lest some watchful sentinel dashes at some springs from the threshold of his hive into the regions | unprotected part of his person.

When beekeepers are standing near hives, single i to summit. The river Dwyryd runs deep below you bees very frequently make close examinaiion of the at the bottom of the vale, while Moelwyn rises from intruder. I am constantly the object of their close

a tree-covered breastwork of hills in a great and attention. Perhaps the little examiner is but passing

serried scarp from Tan-y-Bwlch to Blaenau Ffestiniog away a spare moment by way of recreation, probably,

slate quarries. Its beauty, to my mind, is its variety, mistrustful, he is warning me to give his home and

the contrast between the ornamental nature of its friends a wider berth. First he buzzes within an inch

foreground of hills, and the steep treeless scarp of its of one eye, then visits its fellow, then makes a tour

main mass. Facing the south-east, it changes much of inspection, sounding his trumpet first in one ear, under the varying light of the sun, now lighted up in then in the other, his observations being almost en every detail of its structure, and anon a vast mystery tirely confined to the head.

When I hear his l of gloom. A descent from the village of Ffestiniog

When I hear his threatening buzz, knowing that he is not to be trifled

to the Dwyryd down a steep footwalk gives us some with, and wishing to spare his life, I close my eyes

very picturesque views. The vale is well wooded. and remain quite stationary, and, after awhile, my

We cross the river by a foot-bridge, noticing, by the little friend, seeing that he has nothing to fear, settles

way, some well-rounded boulders in the river bed. usually upon my face, sometimes the lobe of an ear,

Ascending the other bank we strike the main road more frequently the tip of my nose, and after a few

which skirts a deep and picturesque ravine thickly preliminary brushings up pursues his peaceful way,

timbered. Arriving at the turnpike, we turn towards and I mine. We have become better acquainted,

Tan-y-Grisiau, noticing a large bank of drift which and he is far less likely to trouble me on any future

lies near the fork of two streams, one of which occasion, whereas a timid person would, by his frantic

rises in Cwm Orthin, the other nearer the slate provoke a catastrophe. His terror may perhaps quarries of Blaenau. The road to Tan-y-Grisiau be excused, when it is remembered that the dislike is

skirts the former stream, in which are two very probably mutual ; bees' antipathy to particular indi.

picturesque falls. The lower fall is crossed by a viduals being as remarkable as their liking for others,

bridge just above it. Passing over this, with some and, whilst some persons may handle them with im

climbing through ferns and heath, and over walls. punity, there are others who dare not venture within

ascending the right bank of the stream, we get a very yards of their hives without being attacked. That

beautiful view of this upper fall. The rock here is the odour of some persons, not perhaps in itself un

part of a large mass of intrusive Syenite forming Moel pleasant, may yet be disliked by the bees, is the most

Tan-y-Grisiau, and the stream has cut back a deep reasonable explanation of the strange facts that can

gorge into it. Further along, the stream can be again be offered.

crossed by another bridge near to Tan-y-Grisiau. At Swalcliffe, Banbury, Oxon.

the Tan-y-Grisiau station of the narrow gauge or “Toy” railway we begin the ascent of Moelwyn. Skirting the railway and ascending a footpath, not

very difficult climbing, we reach Llyn Trwstyllon, a ARTISTIC GEOLOGY.

cwm lying under the great scarped face of Moelwyn.

The rocks at the open part of the cwm slope towards FFESTINIOG AND ITS NEIGHBOURHOOD.

the lake. The dip is 18° north-west. It appears to be By T. MELLARD READE, F.G.S., &c.

striated south-east, but very faintly. The surface of the TN addition to its reputation for picturesque

rock is much broken up in places since the glaciation. T scenery, and the soft beauties of its vale,

The cwm is a very perfect cup, broken through on Ffestiniog is a very good centre for the geological

| the south-east side. The scenery is very fine. A steep student. Situated on a sort of promontory between

ascent of green turf-covered slope brings us on to the two valleys, the Cynfael and the Dwyryd, at a

back of Moelwyn. The remainder of the ascent is sufficient elevation to maintain a bracing atmosphere,

up what appears from below a small hillock, but the mind and body retain that elasticity which

develops into a mountain when you get on to it. It makes mountain scenery so enjoyable. At the same

is very steep and grass-covered, sheep grazing up to time, those whose delight is the investigation of

the very top. A magnificent view rewarded our nature can fully gratify their cravings. I will

exertions, the weather being delightfully bright and proceed to describe some of the geological problems

clear, and the light breeze exhilarating. I have been which force themselves upon the notice of the

up many mountains, but never saw a finer view than thoughtful mind.

that to the north-west over Snowdon. I preserved my

impressions in a sketch taken at the time, in which SURFACE FEATURES.

the mountain forms are reproduced in outline. It The grand flank of Moelwyn, perhaps the finest represents a grand series of mountains rising in a low mountain of its height I have ever seen, is to my but sublime pyramidal mass culminating in the peak mind of more interest than the much, if not over, of Snowdon. The hollow of Llyn Llydaw, the entrance praised vale. It can be seen at one view from base to the pass of Llanberis, and the Glyders, and other well-known features are distinctly visible. To the ' commerce are interbedded in the series, and as the left is a glimpse of the sea high up in the horizon. beds dip steeply to the north-west the quarrying Moel Hebog, the Glaslyn and pont Aberglaslyn are operations have to be mostly followed by galleries, also distinguishable. The Glaslyn runs like a silver and not in great cuttings open to broad daylight, as streak through a mass of green fields to the Traeth is the case with the quarries at Penrhyn, near Mawr. Beyond is the embankment across the marsh Bangor, which lie in the older Cambrian slates. To for the road and railway terminating in Port Madoc, , the north, in the valley of Dolwyddelan, the calthe houses showing distinct and clear with Moel-y. careous ashes there largely developed are the actual geist in the back.ground, and in the far distance representatives of the Bala limestone and the Caradoc stretches the long promontory of Caernarvonshire till sandstone of Shropshire, and the vast masses of ashes almost lost in the blue haze of the distant sea. The that crown the felstones of Snowdon and Moel Rivals showed like little cobs on the relief map of Hebog are but an enlarged development of the same Caernarvonshire. Further to the west shone the strata.* brilliant orange sands of the estuary of the Dwyryd To understand the present surface form of the below Tan-y-Bwlch, and beyond this was the sea with country, it is requisite to keep in mind the great fact its shore sweeping round to Harlech Castle, which, that the whole of the Upper Silurian strata which with its towers, appeared as a little group of dots. To i formerly covered Merioneth and Caernarvonshire has the south could be seen the Rhinogs, and the long been entirely removed by denudation. It is only scarped face of Cader Idris beyond, and, to the east, when we get as far to the south-east as the river appeared a sea of mountains out of which arose the Vyrnwy, where the great reservoir to supply Liverpool Arenigs and the Arrans. To the north the land rose is being constructed, that we come upon the remains and fell in billowy sweils till lost in the grey haze. of the Upper Silurian, here preserved in a synclinal.

The immediate foreground of the view over Snow. | A general glance at the geological map of North donia is occupied with the remarkable mountain Wales shows the persistent strike of all the rocks called Cynicht. From the road between Tan-y-Bwlch from south-west to north-east. It is along these and Bethgelert this mountain looks like a pyramid ; | lines that the denudation has principally acted, but it is there seen in profile. From the summit of many of the main valleys possessing the same paralMoelwyn we see it as a long ridge with its flanks | lelism of direction. The hard beds of felstone and scored with gullies and talus, which traverse its steep ash, and the intrusive greenstones and other igneous sides like streams till they become confluent in the rocks, have helped to preserve that peaked and ridgy talus cones at the foot. Immediately below, to the character which here gives the distinguishing beauty left, were the rocky north-west precipices of Moelwyn. to the scenery. The day was a perfect day, the clouds floating high, A walk down the north-west slope of Moelwyn the air clear and exhilarating, yet warm.

brings us to Bwlch Cwm Orthin, a pass between I have dwelt upon this view perhaps more than a Cwm Orthin and Cwm Croesor, which lies between gcological article warrants; but let us pause and Cynicht and Moelwyn. Here we may stop to consider if it will yield us any scientific information. examine some slate works. The slates are gener

The traveller about Ffestiniog will soon find out, if ally of small size, but beautifully true and fine. he carries a compass with him, that the general strike Descending the path to Cwm Orthin, we get a good of the rocks is from south-west to north-east. At view of the Llyn below, now being rapidly filled up right angles to this the strata have been thrown into with the debris from the Cwm Orthin slate quarries. a series of anticlinal and synclinal folds, broken up, At the entrance to the cwm may be seen those and, to some extent, obscured, by faults, it is true. well-rounded rocks specially noted by Ramsay as Perhaps this feature in the structure of the country good instances of roche moutonnée glaciation. Beyond can be best appreciated in the general view of the these we may again examine slate works. Here some mountains of Snowdonia obtained on the coast road of the slate is of that peculiarly fine and soft nature between Maentwrog and Harlech. It can, however, which fits it for manufacture into school slates, the be observed on Moelwyn itself. A slate quarry on process of which may be watched. I impressed on

process of which may be watch the back of Moelwyn shows the rock to dip rapidly my mind the view of Cwm Orthin looking towards to the north-west. Without going into details, the the glaciated rocks, in the best possible way, by structure of the mountain is a series of shales and sketching it. It is a true rock basin, the dip of the slates, with an interbedded massive series of felstones strata to the north-west and the hardness of the and felspathic ashes.

felspathic rocks at the outlet, no doubt being deterIt is these hard massive beds which form the grand mining causes, together with ice, in producing this scarp in which lies Llyn Trwstyllon. The whole of form of denudation. A steep down-hill walk brings these beds belong to the Lower Silurian series, us to Tan-y-Grisiau station, but we may pause a commencing with the Lingula beds in the Ffestiniog moment to look at the waterfall. The stream from and Tan-y-Bwlch valley, and terminating in the Balai

* Ramsay, "Memoir of the Geology of North Wales,” ist beds at the summit of Cynicht. The slates of | ed. p. 95.

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