﻿Book Notices. 327 



him eminently fitted to treat the subject as a whole. A companion 

 volume on the Glaciers of North America by the same author, has just 

 been announced. 



The subject is discussed under the heads of the Origin of Lake 

 Basins, the Geological Functions of Lakes, the Topography of Lake 

 Shores, the Relation of Lakes to Climatic Conditions, the Life History 

 of Lakes, and concludes with a special study of the history of three 

 important lake systems, namely, the Pleistocene Lakes of the St. 

 Lawrence Basin, Lake Agassiz and the Pleistocene Lakes of the Great 

 Basin, The numerous illustrations add greatly to the interest of the 

 book. 



The subject of the Origin of Lakes is one which has been much 

 discussed by various writers, and on certain minor points there are 

 still difierences of opinion. But certain great types of lakes can 

 be selected, concerning whose origin there can be no question. 



Thus there are the lakes which occupy depi-essions in what was the 

 old sea bottom, in tracts of country recently elevated above sea level. 

 These are not common in America, for the reason that while large 

 portions of our coast are sinking new land areas are rare. The lakes 

 of Florida, however, are good examples of this class. Other lakes of 

 this type, whose present positions, however, have been partly 

 determined by the rising or sinking of great blocks of the earth's crust 

 along extended lines of fracture, are the lakes of the Great Basin, that 

 vast area of interior drainage between the Sierra Nevada and the 

 Rocky Mountains. Many of these, though still large in size, are mere 

 remnants, left by the evaporation of the very much larger lakes which, 

 in the Pleistocene age, were found in this region. Thus Great 

 Salt Lake and Sevier Lake, Utah, are the remnants of a great inland sea 

 which has been named by Gilbert, Lake Bonneville, while Pyramid, 

 Walker and other lakes in Nevada mark the position of another great 

 body of water which Mr. Russell has called Lake Labontan. 



Another class of lakes are the "Ox-box" Lakes, which represent 

 portions of former river courses which have been cut off by rivers 

 straightening their channels as they wander through a wide flood 

 plain. Such crescent-shaped lakes are found in many places along the 

 course of the Lower Mississippi. Then, again, there are lakes which 

 owe their origin to glacial agencies, and which, owing to the fact that 

 so large a portion of North America was formerly covered with ice, are 

 extremely abundant. These, in some cases, occupy actual rock basins, 

 scooped out by moving ice, while in other cases they lie in the 

 morainic deposits left by the ice upon its retreat. Such lakes, 

 ranging in size from mere pools up to splendid water sheets, many 

 square miles in extent, are so abundant over the formerly ice-covered 

 portion of North America that the position of the southern boundary 

 of the old ice sheet may be approximately traced on an accurate map 

 by noting the southern limit of the lake-strewn portion. In the 



