260 The American Naturalist. [Mareh, 
of Appalachian Structure, Bailey Willis; The Average Elevation of 
the United States, by Henry Gannett; The Renssela r Grit Plateau 
in New York, by T. Nelson Dale; The American Tertiary Aphide, 
by Samuel Hubbard Scudder. 
The same report, Part III, constitutes the fourth in the series of re- 
ports of the Irrigation Survey. The water supply for irrigation is dis- 
cussed by Mr. E. H. Newell, special attention being given to the drain- 
age basins of the Missouri, the Yellowstone and the Platte rivers. The 
principal features distinguishing American irrigation engineering are 
described by Mr. H. W. Wilson, together with the engineering results 
obtained by the Irrigation Survey. Two topographic reports relating 
to the location and survey of reservior sites are contributed by Mr. A. 
H. Thompson. The various reports are abundantly illustrated. 
Reports of the Geological Survey of Arkansas for 1891 and 
1892.°—These two Reports representing Vol. II of the Survey are 
bound in two separate books. The report for 1891 comprises papers 
on the work accomplished by the Survey by Branner, Simonds, Hop- 
kins, and Siebenthal. In addition are Miscellaneous Reports on the 
fauna of the state, magnetic observations and bibliography of the 
Geology of Arkansas to date. 
The report for 1892° embraces the work undertaken by the Survey 
for the purpose of distinguishing the subdivisions of the Cenozoic forma- 
tion of Arkansas and for determining their areal distribution in the 
southern part of the state. This work was accomplished by Prof. G. 
D. Harris. Both Reports are illustrated with a number of well exe- 
cuted plates. 
5 Annual Report of the Geological Survey of Arkansas for 189]. Miscellaneous 
Reports, 1894 
® Annual Report of the oo ae Survey of Arkansas for 1892. Tertiary 
Geology of Southern Arkansas, 
