concludes from his experiments-as many physicists may have concluded from the published account of the supposed new force"that all the phenomena noticed by Mr. Edison are explainable by the presence of inverse electrical currents of considerable quantity, but comparatively small intensity, instantaneously produced at the making or breaking of the battery circuit."

II. GEOLOGY AND MINERALOGY.

1. U. S. Geological and Geographical Survey of the Territories, F. V. HAYDEN in charge. Department of the Interior. Bulletin No. 5, Second series. Washington, Jan. 6, 1876.-This new Bulletin contains the following important papers: A review of the fossil flora of North America, by L. LESQUEREUX; New fossil plants of the Lignitic formations, and from the Dakota group of the Cretaceous, by L. LESQUEREUX; Notes on the Lignitic group of Eastern Colorado and Wyoming, by F. V. HAYDEN; Geology of localities near Cañon city, by S. G. WILLIAMS; On Zapus Hudsonius, and on the breeding habits, nest and eggs of Lagopus leucurus (the white-tailed Ptarmigan), by Dr. ELLIOTT COUES, U. S.A.; List of Hemiptera of the region west of the Mississippi, including those collected during the explorations of 1873, by P. R. UHLER; On the supposed ancient outlet of Great Salt Lake, by A. S. PACKARD, Jr.

The question as to the age of the Lignitic beds is here discussed anew by Prof. Lesquereux with the presentation of some additional facts. His conclusions remain unchanged. They are as follows.-Above the Lower Cretaceous beds or those of the Dakota group, in the Rocky Mountain region, the first fossil plants met with are the species of the Lignitic formation. This formation is divided into (1) the Lower Lignitic, marked by the presence of a profusion of Palms, especially species of Sabal (showing a warm, moist climate, like that of Florida, while the Cretaceous plants of the Dakota group indicate one like the present of Ohio) along with species of Ficus, Cinnamomum, Magnolia, Myrica, Quercus, Platanus, Diospyros, Mamnus, Viburnum, etc. (and as yet no Acer), and referable to the Eocene; (2) the Evanston group, "considered Upper Eocene or Lower Miocene," (3) the Carbon Group (more to the eastward, about long. 106 W.) or Middle Miocene," above which comes (4) the Green River Group, or Upper Miocene. The flora of No. 2 includes thus far 90 species, of which a third are known from No: 1: fruits have been found that have been referred to the Palms, but no leaves; there are also in it dentate and serrate leaves of Salix, Betula, Alnus and Acer. The flora of the Carbon Group is "positively Miocene;" 18 species, or nearly a third of all, are identical with European Miocene plants, and 13 with Arctic Miocene, while a few occur also in the Lower Lignitic (No. 1.)

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Among 23 species from the Point of Rocks, referred to No. 1, or the Lower Lignitic, two occur also in beds to the north of the

United States boundary, called Tertiary by G. M. Dawson, seven are identical with, and five related to, species of the Lower Miocene of Europe, two occur in the Arctic Miocene, three are found also at Golden, eight at Black Butte, and two have some analogy with Cretaceous types.

Hayden, in his remarks on the Lignitic beds, observes that there are lignitic or coal beds in both the Cretaceous and Tertiary formations of the Rocky Mountain region; but that, so far as Eastern Colorado is concerned, from Raton Hills to Cheyenne, the lignitic beds are not associated with marine deposits, but those of brackish water or fresh water origin, and that these are not Cretaceous, but of Eocene age, the evidence from the plants pointing, according to Lesquereux, to this conclusion. He further states that in Southern and Southwestern Colorado, as shown by Mr. Holmes and Dr. Endlich of the expedition, and also other authorities, heavy beds of coal occur all through the Cretaceous. Hence, taking, he says, the whole Rocky Mountain region into view, there is a Lower Liquitic group which is marine and Cretaceous; above this, the Middle Lignitic, brackish water in origin, which is Lower Tertiary or transitional; and next the Upper Lignitic, freshwater in origin, which is unquestionably Tertiary. The coal deposits of Carbon are included in the third of these divisions, and those of Bear River and Coalville in the first. Dr. Hayden observes that Dinosaurian remains occur even in the freshwater or upper division, as noticed by Cope and Marsh; but that the species are not identical with any known Cretaceous species. The Green River beds overlie the Lignitic beds unconformably.

The difference between Prof. Lesquereux's view and those of Dr. Hayden appears to be this: Lesquereux makes the Eocene to include the Bear River and Coalville beds, and all the older Lignetic beds the fossil plants of which he has examined (including those even of Vancouver Island, where Ammonites and Baculites occur in beds overlying the coal); while Dr. Hayden admits that there is a series of Cretaceous coal beds, that the Bear River and Coalville deposits are included in it, and that these Cretaceous strata are distinguished by being mainly marine and containing Cretaceous fossils.

Between the views of Prof. Lesquereux and those of the zoological paleontologists the divergence is great. For while he makes the Green River beds (containing remains of fossil plants and fishes) "Upper Miocene," and the Carbon beds "Middle Miocene," Leidy, Cope, and Marsh hold that even higher strata, namely, those overlying the Green River beds conformably (having an estimated thickness of five or six thousand feet) and which contain the oldest Mammalian remains of that part of the continent, are Eocene; and that the underlying Green River beds are Lower Eocene; and further that all the Liginitic beds, that are older than the Green River beds, are Cretaceous, since they contain Dinosaurian remains, and some of them other Cretaceous fossils,

Thus widely the best authorities differ; partly because European tests of geological age are not always good for use in America, and partly, also, from deficient American testimony. We are disposed, with the present light, to argue the case as follows:

First. It is highly improbable that the type of Dinosaurs should have been represented all through the Eocene and into the Miocene-as must be true if Lesquereux's conclusions are right.

Secondly. Mammalian fossils are a far safer criterion of geological age than fossil plants-since the changes in the species of mammals through the successive eras of the Tertiary are vastly greater than in those of plants; and as the mammals of the beds next above the Green River beds are strongly Eocene in their characteristics-as attested to by Leidy, Marsh and Cope-it is exceedingly improbable that the beds affording the fossil mammals should be Upper Miocene, or Miocene at all.

Thirdly. If the beds containing these mammalian remains, together with the underlying Green River beds, are Eocene, then the Evanston beds, and the Carbon beds also if older than the Green River, are either earlier Eocene or Cretaceous. It follows also, fourthly, that the "Miocene" features of the plants of the Liginitic beds are not due to the plants being of Miocene age; and hence, fifthly, that the diversities in the cotemporaneous Tertiary flora of Europe and North America are so great that little use can be made of the facts from one continent for fixing the chronology of beds in the other.

It is probable, that part of the diversity in vegetation of differ ent localities was owing to local physical conditions, and to migrations consequent on changes of climate with the progress of time during the Lignitic era; and that much of the diversity between America and Europe was due, as suggested by Lesquereux, to many of the Miocene plants of Europe having previously existed as Eocene or Cretaceous plants in America.

If the fossil plants are an uncertain test of geological age, so may it be also, to some extent, with the fossils animals, when characteristic species are sparingly present. Even the existence of Dinosaurian remains in the later Lignitic, and of Inocerami where Ammonites and Baculites are absent, may not prove absolutely that the beds containing them are Cretaceous rather than Lower Eocene, since some animals species may have survived the changes separating the two eras, as has happened in the case of other successive eras.

In the paper, on the former outlet of Great Salt Lake, Dr. Packard points out that General Connor has found, by his railroad surveys, that the lowest part of the including rim of hills is at Skull Valley, west of the lake, and that the height there is "somewhat over 100 feet above the present level of the lake." He adds that the river-bed has been traced southward over 100 miles to the Sevier Lake Valley, passing west of Sevier Lake. It is probable, further, that the river joined the Colorado near the confluence of the Muddy River and Rio Virgen; but it may have had an

independent outlet into the Dry Lake Basin north of east of San Diego, a region seventy feet below the present sea-level. Dr. Packard hence concludes that the lake was once fresh, and that it has become salt by evaporation and contributions from salt springs and the soil.

J. D. D.

2. Drift formation and Gold in Missouri; by G. C. BROADHEAD. The drift of Missouri is confined to the part of the State north of the Missouri. The upper beds are chiefly sand with some small pebbles and a little clay; lower down are large bowlders, and at base are blue clays. In Sullivan Co., and the western part of Adair the depth is 50 to 60 feet; in Davies Co., 40 to 80 feet; in northeastern Adair, over 100 feet; in Knox, 200 feet; in Putnam, over 70. In Illinois, in Moultrie Co., the depth is over 200 feet, as shown by wells, and in Decatur Co., over 90 feet. Gold has been found in Missouri, in Chariton, Linn, Adair, Putnam, Sullivan and Mercer Counties. It is in very small grains, the largest particles, from Adair Co., are not larger than a grain of wheat.-Mines, Metals and Arts, St. Louis, Dec. 9. 3. Glacial striæ north of Lake Ontario, in the Ontario district, Western Canada.-Prof. CHAPMAN, in a paper on the Geology of Ontario (Canadian Journ., xiv, 580, Dec., 1875) states that the limestone strata beneath the glacial and post-glacial deposits (which cover a large part of the Lake Ontario district) are found to be generally striated, and that the striæ run commonly in a southwest direction. The direction proves that the slope of the upper surface of the glacier in that region was from the northeast to the southwest; or that the greatest height of the ice surface lay somewhere to the northeast of that district.

4. New Fucoid from the Water-lime Group (Lower Helderberg) of Western New York. Messrs. A. R. GROTE and W. H. PITT have described a species of Buthotrephis, from the Water-lime, which they call B. Lesquereuxi. The stem, originally cylindrical, branches from the base; and the branches are simple or sparingly dichotomous, smooth, 13 to 14 cm. long, 3 to 4 mm. thick, but gradually widening to nearly 1 cm. at the obtuse or round-truncate point.-Bull. Buffalo Soc. Nat. Sci., 1876 (January), p. 88.

5. Petrifaction. CHEVREUL, in a paper before the French Academy, sustains the view that the petrifaction of an organic substance, as wood, comprises two epochs: the first is that of the filling of all the interstices and pores of the solid body by a solution of the mineral material through capillary action, to fix it chemically by affinity upon the solid portion-producing a petrifaction which has the figure of the interstices and pores; and the second includes the time of the total disappearance of the organic matter itself and its replacement by the mineral material, the result of this action having the actual form of the organic matter. Daubrée, after the reading of M. Chevreul's paper, mentioned facts from the hot baths of Bourbonne-les-Bains confirming his conclusions. He stated that wood occurs in the waters in all states of change by the petrifying agent, carbonate of lime. In

one specimen a portion was nearly 97 per cent carbonate of lime, all the organic tissues but 31 p. c. having disappeared; while in another portion, less changed, only the interstices and cellules were filled by the carbonate of lime. In one specimen the wood nearest the bark and the bark contained no carbonate of lime, as was easily proved by an acid.

6. Green Mountains.—On page 498 of the last volume of this Journal (Supplementary December number), a note is inserted correcting the blunders which have long circulated in Geographies, Gazetteers, Encyclopedias, and New England Guide-books, as to the Green and White Mountains terminating in trap ridges-called West and East Rocks-in the vicinity of New Haven; the fact being that East Rock is but a short appendage (half a mile long) to the system of trap dikes of the Connecticut valley, and West Rock, a southern portion of the same system. Prof. O. P. Hubbard has informed the writer that this extraordinary error in New England Geography has the following forms in "The Imperial Gazetteer" published by Blackie & Son at Glasgow, Edinburgh and London, in 1855. Under NEW HAVEN, "Surrounded on three sides by spurs of the Green Mountains.' Under GREEN MOUNTAINS, A mountain range commencing near New Haven, Connecticut." Under CONNECTICUT, "Some of its mountains, particularly the Green Mountain range," etc.

The Green Mountains consist of metamorphic rocks and are not younger than Silurian. They have their greatest height in Vermont, and there received the name. The mountain system extends south through western Massachusetts and western Connecticut, and the whole is rightly called the Green Mountain chain. But the trap ridges of the Connecticut valley, belong to the valley, and are of Jurassic origin.

J. D. D.

7. Geology of New Caledonia.-The formations of New Caledonia, below the Quarternary, according to M. Garnier, include the Lower Neocomian (Lower Cretaceous); Upper Lias (containing Nucula Hammeri); Lower Lias (containing Ostrea sublamel losa, &c.); Upper Trias (containing Halobia Lomelli); Lower Trias (with Avicula Richmondiana); Upper Devonian and Upper Silurian; besides also crystallized rocks. Among the last mentioned are mica schist and argillaceous slate with quartz veins, some of them auriferous, amphibolite, talcose slate and serpentine, with crystalline limestone. At Koé and Karigou the coal is anthracitic, partly graphitic; and at the latter place it is said to have been rendered anthracitic by a dike of euryte porphyry. To the northwest of Mont d'Or it is bituminous, but impure.

The serpentine or magnesian rocks cover a large part of the island. The serpentine contains bronzite or diallage, chromic iron, magnetite, "hydrosilicate of magnesia," and is traversed by "veins" of chrysolite. It passes into white argillaceous [probably hydro-mica] schists, and these are intimately associated with the serpentinous schists [facts which prove that the serpentine is not, as Garnier states, igneous, but, like most serpentine rocks, meta