378 REVIEWS 
partly formed before Carboniferous time. Professor Shaler believes 
that east of the Appalachians there were developed during Carbonifer- 
ous times a great series of erosion troughs which by sedimentation and 
subsidence became centers of quaquaversal orogenic movement, result- 
ing in foldings with axes variously inclined to one another within the 
same trough. The truncated remains of the folds so produced are to 
be seen at various points along the Atlantic seaboard. That these 
erosion troughs were river valleys and estuaries is suggested by their 
lack of parallel or other definite arrangement such as is seen in the 
Appalachians, as well as by the character of the deposits they contain. 
The Narragansett basin is one of these ancient erosion troughs in which 
the folds were of the anticlinal and synclinal type. The present aver- 
age structural depth of the basin is' placed at 7000 feet, but it is assumed 
that this depth is due mainly to folding resulting from accumulation of 
deposits. [he source of the bulk of the sediments of the basin was 
the immediately surrounding granitic, trappean, schistose and other 
rocks. ‘There are also many quartzitic pebbles of Cambrian age in the 
conglomerates but the source of the similar pebbles of the drift is con- 
sidered unsettled. In discussing the glacial history of the region Pro- 
fessor Shaler expresses the view that this district was one of extensive 
and long continued glaciation during the Carboniferous period and 
that the important features of the upper stratified rocks are due to 
glacial action. 
In the economic section the soils, coals, and iron ores are discussed 
at considerable length. Recent subsidence in the immediate vicinity 
of the basin has caused flooding of old valleys. This and the thick 
covering of drift have rendered geological work difficult, and the 
delimitation of formations uncertain. The volume represents much 
detailed work accomplished in a region presenting more than ordinary 
difficulties. There are many well placed plates and figures to illustrate 
ithestext: R. D. GEORGE. 
On the Lower Silurian (Trenton) Fauna of Baffin Land. By 
CHARLES SCHUCHERT. Proceedings of the U.S. National 
Museum. Vol. XXII, pp. 143-177, with plates XII to XIV. 
At the request of the author, Mr. J. N. Carpender and others (who 
accompanied the Seventh Peary Arctic Expedition as far as Baffin Land 
in 1897,) made collections of fossils from Silliman’s Fossil Mount at 
