ceras; two undetermined species of Platycerinus; three undetermined species of Actinoceras. Mr. Miller remarks that the age of the rocks, if all the fossils are from one range, is that of the Upper Burlington or Lower Keokuk, but if of different elevations, they represent these two groups respectively.

Some specimens are of interest as showing the nature of the process of deposit of silver in the limestone. A Zaphrentis and an Orthis in good preservation, are partially replaced by argentiferous iron, which retains their structual details. This shows clearly that the process is one of replacement of the limestone by a fluid holding the metals in solution, and not by injection. This is also demonstrated by the undisturbed condition of the thin bedded limestone where traversed by veins of ore.-E. D. Cope.

Insects of the AMYZON SHALEs of Colorado.-In the Bulletin of the U. S. Geological Survey of the Territories of Hayden, Mr. Scudder publishes a review of the geology and palæontology of the above deposit. He observes: "The insects preserved in the Florissant basin are wonderfully numerous, this single locality having yielded in a single summer more than double the number of specimens which the famous localities at Oeningen, in Bavaria, furnished Heer in thirty years.

"The examination of the immense series of specimens found at Florissant has not gone far enough to yield data sufficiently definite for generalizations of any value, or which might not be altered, or even reversed, on further study. It may, nevertheless, be interesting to give a running note of what has been observed in assorting the collection, and to make the single comparison with the Oeningen insect fauna which the number of individuals will furnish.

"This is indicated by the following table, based on a rough count of the Florissant specimens, but which cannot be far astray.

"The plants, although less abundant than the insects, are exceedingly numerous, several thousand specimens having passed through the hands of Mr. Leo Lesquereux. Of these he has

published thirty-seven species in his Tertiary Flora, about twofifths of which are considered identical with forms from the European Tertiaries. "We have in all from ninety to a hundred species of plants recognized from these Florissant beds, of which half the species belong to the apetalous exogens.

"The testimony of the few fishes to the climate of the time, is not unlike that of the plants, suggesting a climate, as Professor Cope informs me, like that at present found in latitude 35° in the United States; while the insects, from which, when they are completely studied, we may certainly draw more definite conclusions, appear from their general ensemble to prove a somewhat warmer climate. White ants are essentially a tropical family, only one or two out of eighty known species occurring north of latitude 40°. In North America only three have been recorded north of the border of the Gulf of Mexico, excepting on the Pacific coast, where one or two more extend as far as San Francisco. Two species, both belonging to the second section, are found in the valleys below Florissant, in 39° north latitude. Florissant itself is situated 2500 meters above the sea, and the presence of so considerable a number of white ants embedded in its shales, is indicative of a much warmer climate at the time of their entombment than the locality now enjoys. Investigation. of other forms increases the weight of this evidence at every step, for nearly all the species (very few, certainly, as yet) which have been carefully studied, are found to be tropical or sub-tropical in nature. As, however, most of those studied have been selected for some striking feature, too much weight should not be given to this evidence."

This subject will be discussed in a forthcoming volume of the Report of the U. S. Geological Survey of the Territories of Dr. Hayden. The illustrations of this work which we have seen are of unusual excellence.

THE FUTURE OF GEOLOGY.-Professor Ramsey, in his address before the British Association, said that in the British Islands the art of geological surveying has, he believed, been carried out in a more detailed manner than in any other country in Europe, a matter which has been rendered comparatively easy by the excellence of the Ordnance Survey maps both on the 1-inch and the 6-inch scales. When the whole country has been mapped geologically little will remain to be done in geological surveying, excepting corrections here and there, especially in the earliest published maps of the Southwest of England. Palæontological detail may, however, be carried to any extent, and much remains to be done in miscroscopic petrology which now deservedly occupies the attention of many skilled observers.

It is difficult to deal with the future of geology. Probably in many of the European formations more may be done in tracing the details of subformations. The same may be said of much of

North America, and for a long series of years a great deal must remain almost untouched in Asia, Africa, South America, and in the islands of the Pacific ocean. If, in the far future, the dayshould come when such work shall be undertaken, the process of doing so must necessarily be slow, partly for want of proper maps, and possibly in some regions partly for the want of trained geologists. Palæontologists must always have ample work in the discovery and description of new fossils, marine, fresh-water, and truly terrestial; and besides common stratigraphical geology, geologists have still an ample field before them in working out many of those physical problems which form the true basis of physical geography in every region of the earth. Of the history of the earth there is a long past, the early chapters of which seem to be lost forever, and we know little of the future except that it appears that "the stir of this dim spot which men call earth," as far as geology is concerned, shows "no sign of an end."

MINERALOGY.1

PHYTOCOLLITE, A NEW MINERAL FROM SCRANTON, PA.-This name has been given to a very curious, jelly-like mineral recently found near the bottom of a peat bog at Scranton, Pa. An excavation for a new court-house had cut through a peat bog, below which was a deposit of glacial till. Near the bottom of the bog, in a carbonaceous mud, or "swamp muck," there occur irregular veins, of varying thickness and inclination filled with a black, homogeneous jelly-like substance, elastic to the touch. This substance becomes tougher on exposure to the air, and finally becomes as hard as coal. When thus dried, it is brittle, has a conchoidal fracture and brilliant lustre, and closely resembles jet. It is nearly insoluble in alcohol and ether, but is entirely soluble in caustic potash, forming a deep reddish-brown solution, from whence it can be again precipitated on the addition of an acid. It has a specific gravity of 1.032 and burns with a bright flame. After having been dried at 212°, it has the following composition, according to the analysis of J. M. Stinson:

yielding the empirical formula C10 H22 O16

In its mode of occurrence and in general appearance, this substance closely resembles Dopplerite, but differs from that mineral

1Edited by Professor HENRY GARVILL LEWIS, Academy of Natural Sciences, Philadelphia, to whom communications, papers for review, etc., should be sent.

H. C. Lewis, Proc. Amer. Philos. Soc., Dec. 2, 1881.

in burning with flame and in its composition. Another jelly-like substance from a Swiss peat bog, differing both from Dopplerite and from the Scranton mineral has been described by Diecke.

It is now proposed to group all these jelly-like minerals, produced by the decomposition of vegetable matter, under the one generic name of Phytocollite (φυτόν, κόλλα Ξ "plant-jelly ") of which the three minerals now known would be varieties.

Special interest is attached to these substances, in that they illustrate the first step in the transformation of peat into coal.

COSSYRITE. Förstner1 has given this name to a hornblendic mineral which abounds in the igneous rocks of the Lipari islands. It occurs in triclinic crystals closely approaching monoclinic forms. It has an easy cleavage in two directions, the included angle being 65° 51'. Spec. grav. 3.75. It has the following composition.

SiO2 Fe2O3 A1208 FeO MnO CuO CaO MgO Na2O K20 43.55 7.97 496 32.87 1.98 .39 2.01 .86 5.29 -33 Before the blowpipe it melts readily to a brownish-black glassy slag. It is partially decomposed by acids. It appears to be a variety of iron amphibole.

ALASKAITE.-A new sulphide of bismuth and lead from Alaska mine, Colorado, has been described by Dr. G. A. König. It occurs as a pale lead-gray mineral of scaly structure and metallic lustre, which forms a more or less intimate mixture with quartz, barite, chalcopyrite, etc. It is soft, and has a spec. grav. of 6.878. In the closed tube it decrepitates and fuses. On charcoal gives characteristic coatings. It is soluble in sulphuric acid. It has the following composition:

The formula given is (Pb, Zn, Ag2, Cu2) S + (Bi Sb)2 S3.

PSEUDOMORPHS OF COPPER AFTER ARAGONITE.-Domeyko has described some interesting cases of pseudomorphism of copper after aragonite observed in some Bolivian mines. He found hemitropic crystals of aragonite presenting all degrees of transformation into metallic copper, and showing every transition from crystals of pure aragonite to those of pure copper.

ELECTRICITY DEVELOPED BY THE COMPRESSION OF CRYSTALS.— Jacques and Curie3 have shown that by the mere compression of an inclined hemihedral crystal, electricity is developed. They experimented by placing a crystal or a suitable section of it between two sheets of tinfoil insulated on the exterior by plates of 1 Zeits. f. Kryst., v, 1881, p. 348.

2 Zeits. f. Kryst., 1881, VI, 42.

3 Bull. Soc. Min. de France, 1880, 93. Comp. Rend., 1881. IV, 186, and VII, 250.

caoutchouc, the tin foil being connected to a galvanometer. By now compressing the crystal in a vise or otherwise, electricity is developed and may be measured by the galvanometer. The electricity developed is the opposite of that produced by heating a crystal,—that is to say, the extremity of the crystal which becomes positive on heating, becomes negative on compression. On releasing the pressure, electricity of an opposite kind is produced. The authors find that the production of electricity by pressure can only be obtained with hemihedral crystals having inclined faces. By combining a number of such crystals in a pile, they have invented a new apparatus for producing electricity. The amount of electricity developed varies for different minerals. They find, for example, that a section of quartz, cut perpendicular to the main axis, evolves more electricity than a similar section of tourmaline.

NOTE ON GOLD.-There is a simple method for the detection of gold in quartz, pyrite, etc., which is not generally described in the mineralogical text-books. It is an adaptation of the wellknown amalgamation process, and serves to detect very minute. traces of gold.

Place the finely powdered and roasted mineral in a test tube, add water and a single drop of mercury; close the test tube with the thumb and shake thoroughly and for some time. Decant the water, add more and decant repeatedly, thus washing the drop of mercury until it is perfectly clean. The drop of mercury contains any gold that may have been present. It is therefore placed in a small porcelain capsule and heated until the mercury is volatilized and the residue of gold is left in the bottom of the capsule. This residue may be tested either by dissolving in aqua regia and obtaining the purple of Cassius with protochloride of tin, or by taking up with a fragment of moist filter paper, and then fusing to a globule on charcoal in the blowpipe flame.

It is being shown that gold is much more universally distributed than was formerly supposed. It has recently been found in Fulton and Saratoga counties, New York, where it occurs in pyrite. It has also been discovered in the gravel of Chester creek, at Lenni, Delaware county, Penna. In one of the Virginia gold mines wonderful richness is reported, $160,000 worth of pure gold having been taken from a space of three square feet.

A NEW TEXTBOOK OF MINERALOGY.-The mineralogists of Germany are fortunate in possessing a new and valuable work on mineralogy by Professor G. Tschermak. This work, the first volume of which has recently appeared, contains a full description of the physical, optical and crystallographic characters of minerals, and of the various delicate means of investigation at the command of modern mineralogists. Under the head of physical mineralogy an account is given of the latest discoveries