B 
E 
Ee 
if 
Ee 
ae 
a 
ee 
112 Scientific Intelligence. 
tten, 
The thickness, geographical range, general physical characters, charac- 
teristic fossils, &c., of each of these rocks are also stated in considerable 
detail. This chapter likewise includes an interesting Report by Prof 
G. J. Brush of Yale College, on the geodes so abundant at the Rapids of 
the Mississippi in the Keokuk beds. 
The Devonian and Silurian rocks are similarly treated of in chapter 
IV; while in chapter V, we have a valuable and highly interesting Re 
port on the Galena Lead region, by Prof. J. D. Whitney, now the State 
Geologist of California. Prof. Whitney’s Report is illustrated by a large, 
neatly engraved and colored map of the Lead region, on which the 
boundaries of the several formations, the position and bearings of Jead 
crevices, and the general topography of the country are accurately laid 
down. It also contains another map on a larger scale, of the country 
around Galena, on which similar information is given in more detail: 
likewise a columnar section showing the various rocks that occur in the 
outcrops to each other, and to those of Kentucky, Arkansas, 
Indiana, Ohio and Pennsylvania, as determined by a careful study of the 
fossil plants found associated with each of these beds. From the long 
es. 
e chemical Report of Dr. J. V. Z. Blany, chemist of the survey; — 
constitutes Chapter VIII. This Report contains much valuable informa — 
consisting of numerous analyses of coals, iron ores, &c., chiefly the 
are reported upom — 
by Mr. Henry Engelmann, viz:—Johnson, Pulaski, Massac and Pope. — 
These county Reports are all in great detail, and contain a large amount 
of practical and scientific information. 
