
1891.] Geology and Faleontology. 823 
east by north of San Francisco. H. W. Turner reports that it consists 
of a central mass of metamorphic rocks. The strata immediately sur- 
rounding the metamorphic mass are, except for a space on the south- 
west, of Cretaceous age. Next to the Cretaceous, going away from the 
mountain in any direction, are Eocene (Tejon) strata, and these are 
followed successively by Miocene, Pliocene, and Plistocene deposits. 
(Bull. Geol. Soc. Am., Vol. II., pp. 385-414.) 
Cenozoic.—M. Depeéret has recently published a list of the fauna 
from the different Pliocene beds of Theziers. It contains 302 species, 
and many varieties, of invertebrates, comprising 112 Gastropods, 107 
Lamellibranchs, 3 Pteropods, 5 Brachiopods, 3 Crustaceans, 4 Echino- 
derms, 7 Polyps, and 1 Bryozoan. This is much the most extensive 
that has been given for any single formation of the valley of the Rhone. 
(Bull. No. 6, Tome II., de la Carte Geol. de la France.) ——M. Gaudry 
announces the discovery of mastodon remains near Chérichira, in 
Tunis, probably the jaw of M. angustidens, similar to that of the Mid- 
dle Miocene of Sansan. (Rev. Sci., Ju 20th, 1891.) In a recent 
paper (Bull. Wash. Philos. Soc., Vol. XI., pp. 385-410.) on the 
Mohawk beds in Eastern California, Mr. Henry Ward reaches the fol- 
lowing conclusions: ‘“ The Mohawk valley is the bed of a Plistocene 
lake caused by the damming up of the cañon of the Feather River 
y a flow of andesitic lava. Glaciers existed contemporaneously 
with the lake.’’ According to R. Ellsworth Call, the Loess of 
Eastern Arkansas is Plistocene ; the gravels and sands, Tertiary ; and 
the lower clays, as indicated by the few fossils found, are Eocene Ter- 
tiary. The Loess about Helena is rich in fossil land-shells, but in 
general the fossiliferous exposures are few. Minerals of economic 
importance are not to be found, nor are the lignites of any importance 
from an economic standpoint. (Ann. Rept. Ark. Geol. Sur., 1889.) 
Recent researches by W. J. McGee have shown that the Appomat- 
tox formation consists of a series of obscurely stratified loams, clays, 



and orange sands, with local accumulations of gravel about waterways. 
It forms a widespread terrane, almost continuous with the Costal Plain 
between the Rappahannock and the Mississippi. No characteristic 
fossils have been found in it, but its stratigraphic position, unconform- 
ably below the Plistocene, and uncomformably above the Miocene, 
indicates an age corresponding roughly with the Pliocene. (Bull. 
Geol. Soc. Am., Vol. I.) 
Am. Nat.—September.—4. 


