1 74 Tlie American Geologist. March, looo 
REVIEW OF RECENT GEOLOGICAL 
LITERATURE. 
The Geography of Chicago atid its Environs,. By R. D. Salisbury 
and W. C. Alden. (Geog. Soc. of Chicago, Bull. No. i, 64 pp., 1899.) 
The authors state that their purpose is to present an outline of the 
geography of Chicago and its immediate surroundings, and especially to 
sketch in as simple a manner as possible the course of events by which 
that geography was developed. They have succeeded admirably, and 
have written a clear, readable and interesting account which is liberally 
supplied with illustrations. The pamphlet is divided into two parts, the 
first deals with the Chicago plain, its topography, its structure and the 
drift. The second describes the development of the present geography, 
sketching the history of glacial action and the history of lake Chicago, 
that body of water which existed in the Lake Michigan basin and out- 
flowed through the Des Plaines and Illinois river to the Mississippi. 
The features left by this ancient lake, especially the beaches and bars, 
are discussed, as are also the changes which have taken place during 
the present stage of the water. In one place moUuscan remains, which 
are distinctly marine in character, have been found in one of the old 
beaches. On account of certain apparently conflicting considerations 
final judgment concerning the interpretation of these remains is sus- 
pended until further evidence is forthcoming. Some of the data for this 
paper were collected by the junior author in the preparation of a map, 
(soon to be published by the U. S. Geological Survey) of the surface^ ge- 
ology of this region. u. s. G. 
Some Neiv Minerals from the Zinc Mines at Franklin, N.f., and 
Note concerning the Chemical Composition of Ganomalite. By S. L. 
Penfield and C. H. Warren. (Am. Jour. Sci., 158, 339-353.) 
The new minerals hancockite, nasonite, glaucochroite, and leuco- 
phoenicite were taken mostly from the 1,000 foot level of the Parker 
shaft on North Mine hill, where they are associated with native lead 
and copper, clinohedrite, roeblingite, axinite, willemite, vesuvianite, 
datolite, barite, garnet, phlogopite, and franklinite. Careful analyses 
were made of each of the new minerals, and their formulse computed. 
I. Hancockite. This is a brownish-red mineral crystallizing in 
very minute lath-shaped crystals resembling those of epidote. Hard- 
ness, 6.5-7. Specific gravity, 4.030. The analysis gives the empirical 
formula H.R4"Rr,"'Sio02o or R."(R"'.OH)R."'(Si04)3. The general 
formula is that of epidote, differing principally in having the bivalent 
metals lead (18.53 P^r cent.) and strontium (3.89 per cent.) isomor- 
phons with calcium. It should be placed, therefore, in the epidote 
group next to piedmontite. It is named after E. P. Hancock, of Bur- 
lington, N. J. 2. Glaucochroite. Glaucochroite occurs in small 
orthorhombic prisms or columnar aggregates, and is sometimes 
twinned. It has a hardness of about 6, a specific gravity of 3-407. 
and in color is a delicate bluish green. The analysis, disregarding 
