Itei'lew of Recent Geological Literature. 57 
the earliest known life, and if the rocks are of Torridonian 
age it must even antedate the deposition of those ancient 
hitherto Azoic strata of Scotland. The theoretic deductions 
herefrom are many, striking and important. e. w. c. 
REVIEW OF RECENT GEOLOGICAL 
LITERATURE. 
Pleiatoceni' Features and Dejwuils of tlte Chicago Area. Frank 
Levereti\ (Bulletin of the Chicaf,'o Academy of Sciences. 1897. j This 
paper contains a summary of Mr. Leverett's work upon the moraines 
and drift sheets of the country lying within about 100 miles of Chicago. 
It gives an account in considerable detail of the various lines of drift ma- 
terial as they are now growing more distinct and distinguishable under 
careful and persistent scrutiny, to which result Mr. Leveretfs own la- 
bors have in a very large degree contributed. He recognizes the follow- 
ing series of sviccessive glaciations: 1. The Albertan or oldest (of Dr. G. 
M. Dawson) which has not been found in the district. 2. The Kansan, 
to which belongs great part of the drift sheet of southern Iowa and 
Missouri, which also scarcely enters the area. 3. The Illinoian, which 
includes a sheet covering western Illinois and a small part of southeast- 
ern Iowa. 4. The lowan "upper till" of McGee, contemporaneous with 
the great "loess" sheets of the west. 5. The early Wit^consin with four 
substages indicated by minor moraines, and 6, The later Wisconsin 
with three substages, including the massive Valparaiso system skirting 
the southwestern shore of lake Michigan. 
Mr. Leverett reviews the evidence regarding the relative dates of these 
various ridges which is drawn from the amount of erosion, leaching, in- 
termediate soil, and forest growth and other sources. The data indi- 
cate a succession of ice-invasions from different sources, the most exten- 
sive of the series overriding the deposits of the earlier ones and to a 
great degree or altogether defacing them, while those that followed left 
on the surface their terminal moraines and other monuments to indicate 
the limits of their southern advance. In this way a rudely coni-entric 
stucture of massive ljut gently slojjing ramparts was biiilt up around 
the south end of lake Michigan and other salient points on the northern 
Une of the ice front, the tracing of which is the subject of the present 
work. The paper is illustrated with several maps and some good photo- 
graphic reproductions of exposures in the works of the Chicago drainage 
■canal, etc., (most of which are the work of Gayton Douglass of Chicago) 
and the author closes with a discussion of the present changes going on 
around lake Michigan and the lapse of time which they express. 
E. w. c. 
Papers ami Notes on the Genesis and Matri.,r of the Diamond. By 
the late Henky Cabvit^l Lewis; edited from his unpublished manu- 
