272 The American Geologist. April, 1897 
face of the fourth sheet of drift is altogether inconsiderable. 
The amount of change that has taken place since the begin- 
ning of the interval up to the present time is comparatively 
small. 
IX. Fifth glacial stage, Wisconsin. The last invasion of 
Iowa by glacial ice occurred in times so recent, geologically 
speaking, that the youngest sheet of till exists practically in 
the condition in which the glacier left it. The area in Iowa 
affected by this last invasion is nearly triangular in shape, the 
base of the triangle coinciding with the north line of the 
state from Worth to Osceola counties, with the apex located 
at Des Moines. In the northern part of this area there are 
numerous stretches of ill-drained lands, the surface is only 
very gently undulating and the stream channels, where defined 
at all, have cut only a foot or two into the prairie sod. 
X. The recent stage, since the retreat of the Wisconsin ice, 
brings Pleistocene history down to the present. The recent 
stage, while long as measured in years, has been too short to 
produce any appreciable effect in the surface of the Wisconsin 
drift. s. c. 
REVIEW OF RECENT GEOLOGICAL 
LITERATURE. 
The University Geological Survey of Kansas, volume ii, by Erasmus 
Haworth and assistants. (Pp. 318, plates xlviii, Lawrence, 1897). Al- 
though the University survey has been somewhat hampered by lack of 
funds for their work, yet through the perseverance and untiring efforts 
of its director, aided by competent assistants, a second volume has been 
issued which is even better than the first report. In the first volume 
the stratigraphy of the eastern portion of the state was given, and vol- 
ume II deals with the stratigraphy of the western portion, including the 
Cretaceous and younger formations. The report opens with an intro- 
ductory sketch of Kansas geology, followed by a description of the physi- 
ography of western Kansas. At the close of Cretaceous time, the 
westward drainage system of eastern Kansas was turned eastward, so 
that with the opening of the Tertiary, probably late Miocene division, 
the drainage was .similar to the present while the climatic conditions 
appear to have been very different. The two formations are separated 
by a time interval shown in the extensively eroded Cretaceous surface. 
Over half the Tertiary material is in the form of silt, clay and sand. 
The arroyos or short streams have great width of channel, very abrupt 
banks, and are dry during the greater portion of the year. Associated 
