124 The American Geologist. February, v.m. 
meters west of its present position, and also shows that the processes 
which shifted the divide and reversed the drainage are largely responsi- 
ble for the peculiar features of the Sundal system, namely, its deep 
canyons and high shallow tributary valleys. 
The author reconstructs the mature valley system (Opdal), de- 
scribes the young canyon system, shows the relation existing between 
the two and offers explanations for these relations. He discusses as 
factors in the reversal of drainage : guided headward erosion by the 
Sundal system and capturing of the Opdal branches, unguided head- 
ward erosion and capturing, erosion by the outlets of ice-dammed lakes 
which overflowed from the Opdal to the early Sundal system and 
glacial erosion. 
The text is accompanied and elucidated by five diagrams which 
put the whole story in clear and concise form. The paper is an ad- 
mirable result of thorough investigation in the field and laboratory. 
F. B. 
Bulletin No. 4, of the South Dakota School of Mines, Department of 
Geology. Prof. C. C. 0'H.\rr.\. April, igco. Rapid City, S. Dak. 
This pamphlet, containing 88 octavo pages, with several plates re- 
producing old maps, furnishes an exact and very useful epitome of the 
literature of the geology of the Black Hills. Many of the old papers, 
now very rare, beginning with those of Dr. Prout in 1846, are an- 
notated. The first portion of the bulletin .sketches rapidly the pro- 
gress of geological investigation in the Black Hills region, giving some 
account of the parties and the routes they followed. The earliest men- 
tion of the hills is in Lewis and Clarke's report of their expedition in 
1804-05-06, where they are credited with glaciers, although this must 
have hppn inrorrect — or at least it cannot now he affirmerl of the re- 
gion known as the Black Hills. The author mentions fully the work 
of Dr. Evans in the "bad lands," reported by Dr. Owen in his re- 
port on Iowa, Wisconsin and Minnesota, of Dr. F. V. Hayden and Mr. 
F. B. Meek, Dr. Leidy, Lieut. G. K. Warren and others to 1900. 
N. H. w. 
MONTHLY AUTHOR'S CATALOGUE 
OF AMERICAN GEOLOGICAL LITERATURE 
ARRANGED ALPHABETICALLY, 
Adams, F. D. 
Memoir of Sir J. William Dawson. (Bull G. S. A., vol 11, pp. 
550-580, I goo.) 
Alden, Wm. (R. D. Salisbury and) 
The Geography of Chicago and its environs. (Bull Geog. Soc. 
Chicago. No. i, pp. 64, plates and maps, 1899.) 
