the outburst of trachyte, forming those hills, caused frightful distortion of the Laramie beds. It is clear, then, that the Galisteo group can not be conformable to the Laramie. The former group does not cross the Galisteo creek at any point.

The lower sandstone of the Galisteo group was followed up the creek for more than seven miles above Galisteo, and its ashen color gives a strange appearance to the deeply eroded face of the mesa. The vertical yellow and almost white sandstones of the Lower Dakota yield readily to the weather and the debris from the light gray Galisteo sandstone mingles with that from these; so that, to one ascending the creek and following the line of the eastern fault, the Galisteo sandstone seems to be triple, white, yellow and gray, whereas the white and yellow belong to the Lower Dakota, on which the Galisteo sandstone rests unconformably.

The coal beds of the Placer mountains, occupying the plateau between those mountains and Galisteo creek are synchronous with those of the Trinidad coal field and belong to what is known as the Laramie group, which, however, is synonymous, in part at least, with Fox Hills.

The Galisteo group rests unconformably on the Laramie and Dakota; and contains a great bed composed wholly of the later lavas; it is therefore Tertiary.

ART. LIX.-Short Notes upon the Geology of Catoosa County, Georgia; by A. W. VOGDES, U. S. Army.

A SHORT distance west of Catoosa Station, on the Western and Atlantic Railroad, we find a small cut which exposes the rocks of the Niagara period. This formation is composed in descending of the following strata:

1. Thin bed of limestone made up of crinoidal joints. 2. Cherty bed containing the columns of Caryocrinus. 3. Shaley beds with concretions.

4. Black slate containing about fifty per cent of bituminous

matter.

This outcrop in the valley of the Chickamauga is not over ten feet in thickness and dips about twenty-five degrees to the east. A few hundred yards to the west along the river bank, the topography of the country becomes more hilly, and the railroad passes through a cut of about 100 feet. On the map of the county this is known as section 28, lot no. 204, or Taylor's Ridge. This section exposes an outcropping formation of the Upper Silurian Age which belongs to the Clinton

Epoch. The upper beds are thin and composed of an arenaceous limestone, containing fragments of Crinoids and shells more or less wave-broken, as if this stratum marked the line of the Clinton sea. Immediately beneath the limestone we find a laminated sandy bed intermixed with sandstone of different degrees of hardness, which is well exposed in the railroad cut and along the banks of the Chickamauga River. The total thickness of these beds is about 150 feet, the strata having a general dip 15° east.

The geological formation of Taylor's Ridge is more clearly defined with regard to the Upper Silurian age about ten miles southeast from Catoosa station, at Dug Gap in Whitfield county. This section exhibits the Lower Silurian black shales outcropping along the base of the gap, dipping about twenty-five degrees to the east, and known in Dalton as the "coal beds;" immediately above these shales the Medina sandstones appear or a sandstone which stratigraphically may be assigned to this group; as far as examined it contains no fossils. Superimposed upon these sandstones along the second bench of the Gap we find the Clinton, which is composed in descending order of the following strata:

1. Arenaceous layers and sandstone.

2. Hematitic layers containing Calymene Clintoni, C. rostrata, and generally trilobitic.

3. Arenaceous shales.

4. Sandstone containing Streptorhynchus subplana.

5. Hard sandstone containing hematite.

6. Light sandy beds of the Medina.

The best section examined is about twenty feet in thickness, but the measured thickness of the Clinton gives about 150 feet.

In order to illustrate the true geological sequence of Taylor's Ridge it is necessary to trace the different rocks from Atlanta to Ringgold, but at present we will simply give the section at Ringgold, which is about four miles to the west of our first section, taken near Catoosa station. The town of Ringgold is located in a valley composed of the Trenton limestone. This group is highly fossiliferous; it has a northwest and southeast strike, dips fifteen degrees to the east, being composed of a flinty rock, underlaid by a chocolate-colored shale, which is generally denuded; these shales are underlaid by a blue limestone of over three hundred feet in thickness. Superimposed and forming the hills is a great mass of red laminated sandstone of the Hudson River group. These sandstones are about five hundred feet in thickness, dip nineteen degrees east, one mile east of Ringgold in the gap, and contain only a few specimens of Orthis testudinaria.

Between Ringgold and Catoosa Station the Chickamauga river divides the ridge; the hills to the northwest are called Oak Mountains, and those on the southeast Taylor's Ridge. After passing through this gap the eastern exposure of these hills shows the overlying Medina, Clinton and Niagara groups.

The paleontological characteristics of this outcropping stratum of the Upper Silurian periods are interesting, especially the fossils of the upper beds. These fossils are poorly preserved and consist generally of casts. From our collection we have been enabled to indentify the following species:

Calymene Clintoni Hall; Cryptonymus (Encrinurns) ornatus Hall and Whitfield; Cryptonymus (Encrinurus), Illenus, Proetus; Leperditia, sp., having the right valve marginated by a furrow, except along the dorsal edge, as in L. marginata; Othis elegantula, a species common to the Clinton and Niagara group; Chatetes lycoperdon, cast from the lower beds: Zaphrentis bilateralis?, broken specimens from the upper bed; Conularia, sp. ?

Of the Cryptonymus ornatus we have in our collection two pygidia which we have assigned to this species, although the casts do not show the nodes ornamenting the axis and pleuræ. The specimens compare otherwise with Professor Hall's type given in Palæontology of New York, vol. ii, pl. lxvia, fig. 1a. Vertical distribution Clinton group.

There is also a new trilobite, Calymene rostrata Vodges, from the upper arenaceous limestone beds of the Clinton group, Catoosa Station, Georgia, which will be fully described hereafter. It differs from all other species of this genus in having a distinct projecting process in front of the glabella. The facial lines cut the anterior border at the apex, giving to the frontal limb a triangular form; at their juncture the marginal border is raised and forms the triangular process which supports the projection.

SCIENTIFIC INTELLIGENCE.

I. CHEMISTRY AND PHYSICS.

1. On Electrolysis with Alternating Currents.-Supposing that certain chemical transformations in the living organism are due, not to reduction or oxidation alone, but to both combined, DRECHSEL has devised a method for subjecting a liquid to reduction and oxidation in rapidly alternating succession. For this purpose, the electrodes of a Grove battery of 4 to 6 cells are placed in the solution, an automatic commutator being included in the circuit, so as to reverse the current rapidly. Each electrode thus becomes alternately positive and negative, first oxygen and then hydrogen being alternately evolved on its surface in the nascent state, each exerting its special action upon the dissolved substance. The

The

first solution experimented with was one of ammonium carbonate, the same as is used as a reagent. The electrodes were of platinum. Gas was actively evolved, the temperature rose, and after eight hours the experiment was interrupted and the liquid was evaporated on the water bath. From it a salt crystallized out in beautiful white needles. On analysis it was found to contain 64-69 per cent of platinum and was evidently a salt of a platinum base. The small quantity prevented complete investigation; though its solution gave with concentrated hydrochloric acid a bright green and with nitric acid a sky-blue crystalline precipitate. electrodes lost in ten hours 01 gram; while when the electrolysis was conducted with a continuous current in the ordinary way, no platinum at all could be detected in the solution and at most only 0-002 gram had been transported from the anode to the cathode. On repeating the experiment with a less rapid alternation of the current, the liquid became warm, but gave no precipitate; on cooling it, however, during the experiment, an abundant crystalline precipitate was formed, which though also a salt of a platinum base, contained only 38.6 per cent of platinum, and gave with hydrochloric acid, not a green but a colorless crystalline powder consisting of microscopic needles. Finally, a solution of grape sugar mixed with sodium phosphate was submitted to alternating electrolysis, using platinum electrodes of large size, contact being prevented by a disk of filter paper between them. At the close of the experiment, there was formed on the platinum, at the place where the paper had rested against it, a brownish, transparent crust, easily separated into plates, and which left on combustion a considerable amount of platinum. The author is continuing his experiments upon this new method.

In a note to this paper, KOLBE says that the highly interesting observations of Drechsel raise the question of the behavior of salts and salt-solutions of inorganic and organic acids in presence of powerful and alternating voltaic currents; as, for example, whether an aqueous solution of potassium acetate suffers decomposition without accompanying oxidation. Since Drechsel does not purpose to extend his studies in this direction, Kolbe intends to examine the action of a series of salts under these conditions.J. pr. Ch., xx, 378, Oct., 1879. G. F. B.

2. On the Basicity of Dithionic or Hyposulphuric Acid.-It has been generally assumed that hyposulphuric acid is dibasic and hence that its formula is H,S,O. KOLBE has written it in COOH his Lehrbuch SO,OH or di-sulphoxyl, as oxalic acid is {COOH or di-carboxyl. If this view be true, hyposulphuric acid should form, not only normal salts, but also acid, and mixed salts. Kolbe has set several of his students at work to endeavor to form either an acid salt or a mixed salt, an ether acid or an amic acid, of hyposulphuric acid, but without effect. Since all these bodies are readily given by oxalic acid, Kolbe comes to the conclusion that hyposulphuric acid is monobasic and contains but one hydroxyl

group. Hence the formula of it should be HSO, or (SO)OH. The importance of this conclusion lies in this, that, if it be conceded, the equivalence of sulphur is five in this compound and it becomes a perissad instead of an art iad as it is in all other combinations.-J. pr. Ch., xix, 485, June, 1879.

2

G. F. B.

3. On the Non-existence of Pentathionic acid-In the hope of converting the polythionic acids into a new series of sulphur acids poorer in oxygen, SPRING submitted them to the action of sodium amalgam. But instead of the result expected a very different one was obtained. The sodium inserted itself between the sulphur atoms, splitting the molecule into two simpler ones; just as oxalic acid is converted by hydrogen into formic acid. For example, with tetrathionate, KO,SS. SSO,K+Na,=KO,SSNa+NaSSO,K; with trithionate, KO,S. SSO,K+Na,=KO,SNa+NaSSO,K; with dithionate KO,S. SO,K+Na=KO,SNa+NaSO,K. Precisely as HO,C. CO2H+H ̧=HO,С. H+H. CO,H. In order to test this reaction in the case of pentathionic acid, the author attempted the preparation of this body; but after five months of work he was unable to obtain it. This result raised the question of the existence of this acid. All attempts to prepare it, by the method either of Wackenroder or of Fordos and Gelis resulted only in the production of tetrathionic acid. The action of hydrogen sulphide upon sulphurous oxide in aqueous solution produces hyposulphurous acid; and this is oxidized as it is formed into tetrathionic acid by the sulphurous acid present, the hydrosulphurous acid of Schutzenberger being formed at the same time. Pentathionic acid, therefore, appears to be as yet unknown.-Liebig's Ann., cxcix, 97, Oct., 1879.

G. F. B.

4. On the Atomic Weight of Tellurium.-WILLS has undertaken a re-determination of the atomic weight of tellurium, in order to ascertain whether the value of this constant as at present accepted from the experiments of Berzelius and von Hauer, or the value assumed for it in Mendelejeff's classification, is the more correct. The crude tellurium was purified by fusion with sodium carbonate and sulphur, the fusion extracted with boiling water, the filtrate acidulated with acetic acid, the precipitate well washed, oxidized with nitric acid, evaporated to dryness, heated with hydrochloric acid, the tellurium precipitated by sodium sulphite, washed, dried, fused with potassium cyanide, the fusion treated with water and the deep-claret solution exposed to the air in a flask when the tellurium separates in long needle-shaped crystals. After washing and careful drying these were distilled in a current of hydrogen. The distilled water, nitric and hydrochloric acid used were carefully purified and the accuracy of the weights and balance employed verified. On oxidizing the tellurium with nitric acid, and calculating the atomic weight from the TeO, obtained, the mean of five experiments gave 127.8 with a probable error of 0.32. Four experiments on oxidation with equa regia gave 127.907 with a probable error of 0.053. Five determinations by von Hauer's method, of the bromine in the compound K,Teẞr, gave Te =