Geology and Mineralogy. . 
in charge. Made by authority of the Hon. Secretary of War, 
under the direction of Brig. and Brevt. Major-General A. A. 
Humphreys, Chief of Engineers, U.S. A. 1876.—One of the maps 
of this Atlas has already been noticed in this Journal in volume xi 
(page 161). The completed atlas has recently been issued. It is 
top 
region nearly fifty miles wide either side of the fortieth parallel from 
western Nevada to eastern Colorado. e atlas is a grand con- 
tribution to the Geology of the continent, and bears testimony to 
the very great care and thoroughness of the surveys under Mr. 
King. The five colored geological maps present not only the 
distribution of the several areas of igneous, granitic, and stratified 
trac 
the study of which in the field, by Mr. King, has been supple- 
mented by the exceedingly valuable volume of descriptions by 
Professor Zirkel, forming part of the Reports of the Survey. 
The plates are from the establishment of J. Bien, New York, 
sage land, coal land, gold districts and silver districts; a general 
geological map; six sectional geological maps, and as many topo- 
graphical, on a scale of four miles to the inch; two maps of geo- 
logical sections and one of panoramic views. e areas of the 
memoirs, representing the following species: ©. pune 
Wariolars, é. ‘illatedleis, C. obtusus, C. levis, C. vigilans, C. sex- 
costatus, C. nereus, and C. verrucosus. The limits of the genus 
are those accepted by Eichwald in 1840. It includes Enerinurus, 
and Cybele and Atractopyge are made subgenera under it. 
