324 The American Geologist. November, 1902 
of the glacial drift but also his fine mental characteristics of sincerity, 
modesty, generosity and love of the simple truth. 
An idea of the scope and contents of the volume may be given by 
noting the space alloted to different topics. Of the 759 pages of de- 
scriptive matter in the book, the introduction, including bibliography 
and stratigraphy, occupy 43 pages ; physiography, 16 pages ; ancient 
and present drainage, 138 pages. 490 pages are devoted to the several 
forms of glacial drift, chiefly the moraines. Glacial lakes phenomena 
occupy 66 pages. A short discussion of the soils closes the volume. 
The matter of the book is mostly descriptive, with little in the way 
of theory and philosophy. The only section which is at all speculative 
is that treating of the pre-glacial drainage. But the inferences are mod- 
crate and reasonable and fuller study in the future wil probably con- 
firm most if not all of his suggestions. The aim in the book has been 
not to discuss the glacier with its physical problems, but to describe 
the effects of the glacier upon the district, and to point out, so that 
others may recognize them, the various phenomena which are visible 
today. 
The volume is a marshalling, and to some extent a compilation, of 
all knowledge to date concerning the Pleistocene geology of the area 
treated. Every man who has worked in the field there covered and 
has made his results public will find generous treatment accorded him. 
The geographic area covered in the writing is the glaciated district 
between south-central Indiana on the west and the Genesee river on 
the east. The north boundary is the south line of Michigan and lake.s 
Erie and Ontario. 
In northwestern Pennsylvania, mainly in Warren and Venango 
counties, there is found a limited area of very old glacial drift, the 
Kansan or pre-Kansan, with an outwash far out in the valleys. "The 
state of decay of the local as well as of the foreign stones in this old 
drift, and also the great amount of erosion sustained, put it in striking 
contrast with the fresh-looking and but slightly eroded Wisconsin drift. 
Nearly all the pebbles found on the surface of the old drift have be- 
come so deeply weathered that it is often necessary to break them in 
order to obtain a suflficiently fresh surface to warrant classification. On 
the surface of the Wisconsin drift the same classes of pebbles are still 
so fresh that onh' a glance is necessary to determine their class. As 
the upland portion of this old drift is a thin deposit it is usually deeply 
weathered from top to bottom. In the valley portion weathering is 
very pronounced to a depth of 20 feet or more-'' 
The Illinoian drift occupies a belt outside the Wisconsin drift in 
southeast Indiana and southwest and central Ohio. Eastward beyond 
Holmes county in north-central Ohio the Illinoian drift has been bur- 
ied under the subsequent Wisconsin. The lowan drift does not occur 
in the district outside the border of the Wisconsin, but a deposit of 
silt and loess overlying the Illinoian drift and extending into the un- 
glaciated region is thought to represent the lowan. The interval of 
deglaciation between the lowan and the Wisconsin, called the Peorian 
