11(5 'I'hi A nit rial ii Geologist. February, 1S94 
Lstence of any large mass of meteoric iron, competent to make 
this crater, within at least a depth of many miles. No other 
American maar is known, and the rareness both of such cra- 
ters and <•!' meteoric falls strongly suggests some intimate re- 
lationship. If a erustal steam explosion made the crater, per- 
haps the impact of a large meteorite induced the explosion. 
Thorough knowledge of the altitude, slopes, and general 
contour of any region is so indispensable Tor explorations of 
the conditions of its Pleistocene erosion by streams, glaciers 
and ice-sheets, and of the formation of its glacial and modi- 
lied drift, or of its residuary soils and alluvium if south of 
the glaciated area, that this contribution can not be con- 
cluded better than by noting the several states of which relief 
maps were exhibited in the state buildings and in the Mines 
and Mining building. These were New Hampshire. New York. 
New Jersey. Pennsylvania. Maryland, Illinois, Kentucky, Ar- 
kansas, and California. The one on the largest scab' was New 
Hampshire, the most mountainous of the New England states, 
which was two inches to a mile horizontally, and an inch to 
500 feet vertically. This was made by Air. Cosmos Mindeleli'. 
on the basis of the contoured map published by Prof. C. H. 
Hitchcock, the state geologist, who has shown that the ice- 
sheet covered Mt. Washington, (>.2'.>:> feet above the sea. (here 
moving southeastward. It was displayed in the state build- 
ing, and was surrounded by windows which were transparen- 
cies of White Mountain scenery. In the exhibit of the U. S. 
Geological Survey a relief map of the United States, by Mr. 
Edwin E. Howell, showed the curvature of the earth's surface 
on a scale of forty miles to an inch, which would make the 
earth's radius about eight feet, while the vertical scale was 
exaggerated fivefold, being eight miles to an inch. 
REVIEW OF RECENT GEOLOGICAL 
LITERATURE. 
The Canadian Ice Age: being notes on the Pleistocene geology of 
Canada,with especial referenceto the life of the period and itsclimatal 
conditions, and lists of the specimens in the Museum. By Sir J. 
William Dawson, C. M. G., etc., pp. ix, 301, with numerous illustra- 
tions. Montreal, October, 1893. 
