Review of Recent Geological Literature. 320 
instance, in the Thian-Shan, and along- the marginal curve, for example, 
on the south flank of the Himalaya, by recent plication. The impression 
remains that, since pre-Cambrian time, the movements of Asia have had 
the same character, namely, that of How, especially toward the south, 
but also toward the southwest, west, southeast and east, which reminds 
one of the flattening of the poles. 
In Europe it is different. The oldest movements are represented by 
the pre-Devonian, Scottish and Scandinavian "floor" (Schuppe); there 
follows toward the south and east the Carboniferous and Permian floor* 
rim(Schuppenrand) with man} r later folds, and then the Miocene floor-rim 
of the x\.lps. The movements are also from a very ancient period in the 
same direction; but they are contrary to those of Asia, and have the 
character of confluence toward the north and especially toward the 
northwest. Here also recent movements (namely, the Alps) occur near 
the outside. 
The similarity of the Asiatic movements in taking a general south- 
erly direction, and of the European movements in being prevailingly 
northwestward, with their continuance in these directions during long 
geologic ages, indicates that these movements have been due to original 
heterogeneity of the earth's mass. 
What we call deformation of the earth should be named conformation^ 
namely, the gradual approach to a condition of equilibrium of weight 
as well as of form, which is as yet not fully reached. 
REVIEW OF RECENT GEOLOGICAL 
LITERATURE. 
The Mesozoic EcJiinodermata of the United States, By W. B. Clark. 
(U. S. Geol. Survey, Bulletin 97, pp. 207, with 50 plates, J893. Price, 
20 cents.) Sixty-one species are described here as the entire known 
Mesozoic fauna of this class in the United States. Fifty-one had been 
before described in many scattered publications, and ten appear for the. 
first time. They include 5 crinoids, -I asteroids, and 52 echinoids. All 
are well figured, and a full bibliography is given, making the work ex- 
ceedingly convenient and valuable for paleontologists both at home and 
abroad. The aul hor thinks that many South American echinoderms. 
though described under different names, are identical with the North 
American species: but he doubts that any European Meso/.oic species 
are truly identical, and regards only a few as very closely allied. In 
this opinion he differs from Dr. .1. W. Gregory, of the British Museum, 
who, reviewing the echinoid faunas of North and South America and 
the West Indies, and comparing them with the corresponding European 
faunas (Bulletin, Geol. Soc. Am., vol. in, for 1891, pp. 101-108), consid- 
ers these two faunas on opposite sides of the Atlantic to have been 
