PUBLICATIONS. I15 
argued for, the material of which it is composed being supposed to 
have been derived from the Sioux quartzite or possibly the Carbonif- 
erous of the Mississippi Valley. The author follows King in group- 
ing the Benton, Niobrara and Pierre as Colorado and does not recog- 
nize the Montana, the Fox Hills being mapped alone as the Fox Hills 
Group. In the present state of knowledge this is undoubtedly almost a 
necessity so far as mapping the area is concerned, but it is to be hoped 
that more detailed studies will allow the divisions now so generally 
recognized elsewhere to be differentiated. The White River beds are 
described in detail, especially interesting notes on the presence in 
them of sand-dikes being given. At the Bijou Hills a fine-grained 
quartzite of greenish tinge is noted in the Loup Fork beds. Certain 
obscure beds of sand and clay in the eastern part of the state and in 
part in Iowa are somewhat doubtfully referred to latest Pliocene or 
earliest Pleistocene time and are considered as possible lacustrine 
beds contemporaneous in age with Lake Cheyenne. 
Four moraines are traced: the First or Altamont, Second or Gary, 
Third, and Fourth. On the map these are not marked, the limit of 
drift alone being shown. The drift found in the Black Hills region 
is considered to be “a kind of delta deposit formed by streams 
shifting to and fro upon a plain of deposition.” Some very interest- 
ing facts regarding river terraces which may clear up some of the 
doubt regarding the early history of the rivers in the region are 
given. 
In a résumé of the geological history of the region it is pointed out 
that the eastern half of the State was dry land during Paleozoic time, 
and from this it is argued that the condition for the formation of coal 
existed during the Carboniferous and that mineral may, perhaps, be 
found to occur in the middle of the State. In the chapter on economic 
geology the various minerals, building stones, artesian wells, and other 
similar topics are briefly discussed. 
The report contains the usual number, or perhaps more than the 
usual number, of typographical errors; fortunately, however, very few 
confuse the meaning. It is an exceedingly compact and valuable com- 
pendium of the geology of this comparatively unknown but very rich 
geological province. 
Hi. F. Barn. 
