Rczneiv of Recent Geological Literature. 393 
Retiezc of the Glacial Geology of the Southern Pettinjuta of Michtgatt. 
By Frank Leverett. Reprinted pages loo-iio, from the Sixth An- 
nual Report of the Michigan Academy of Science, 1904. 
This is an excellent condensed summary of the author's elaborate 
observations and conclusions, from extensive field work, aided by Mr. 
F. B. Taylor and others, for the United States Geological Survey. In 
due time their detailed studies are expected to be fully published as a 
monograph similar to the two of Mr. Leverett's authorship already 
issued, which describe the glacial and lacustrine formations south of 
the great Laurentian lakes, from Illinois to New York. 
The full monographic report on this peninsula, between lakes Hu- 
ron and Michigan, will doubtless add much to our knowledge of the 
methods of erosion, transportation, and deposition of drift formations, 
as the following quotation from this advance summary indicates : 
"The structure of the drift is more variable in Michigan, both on the 
surface and below, than in a large part of the neighboring states of 
Ohio, Indiana, and Illinois. In those states the till or commingled 
drift greatly preponderates over sand and gravel, and contains a large 
percentage of fine clayey material. In Michigan sand and gravel form 
a notable part of the drift material, and much of the till is loose tex- 
tured. This great amount of loose textured drift seems attributable to 
the excessive glacial drainage resulting from the convergence of the 
ice lobes. It is best developed in the high portions of the state which 
were built up between the ice lobes. In the plains next to the lake 
basins, where the ice was spreading out, the till or ground moraine is 
compact and clayey, as it is in states to the south w-here the ice lobes 
were free to spread." 
A bibliography of about 50 titles, comprising publications that have 
added materially to the knowledge of the Pleistocene features and 
deposits of Michigan, is appended to this short paper; and it is 
stated that the geologic literature of the Great Lakes includes more 
than 200 titles. w. u. 
Manual of Chemical Analysis of Rocks, by Henry S. Washington. 
Ph.D. New York. Wiley & Sons, 1004. pp. 183. $2.00. 
The great advances that have been made of late years in silicate 
amdyses and the high standards set by modern petrographers. particu- 
larly the advocates of new systems of classification, have, in many in- 
stances, served but to discourage the worker who is dependent wholly 
upon his own efforts for analyses as well as for microscopic research 
and field work. 
The excellent work done by Hillebrand* was a great help, but it has 
remained for Dr. Washington to prepare a manual in which the whole 
field of silicate analysis, so far as is necessary in petrography, has been 
covered in such a manner that no one competent to make analyses at 
all has longer excuse for poor work. 
•Some Principles and Methods of Roclt Analysis. Bull.' 176, U. S. Geol- 
ogical Survey. 
