246 Dewey’s Geological Section. 
animal have been discovered near Cincinnati, and some 
in a good state of preservation in the counties of Athens and 
Meigs. 
References. 
[Print at the end.] 
No. 1,2, B. two views ofa mastodon’s tooth, found in the bed of a 
small river near Pickaway plains, Ohio. Weight, 5lbs. 6 1-2 
inches from A. to r.—from 1. to 1. three inches. 
No. 1, 2, A. two views of a tooth found in alluvial earth, twenty- 
two feet nine inches, below the surface, in digging a salt well at 
the Scioto salt-works. These teeth are in the cabinet of Caleb 
Atwater, Circleville, Ohio. The latter tooth weighs nine pounds, 
though several fragments have been broken off. Its original weight 
was probably from 12 to 14 lbs. at least. 
Art. VI. Geological section from Taconick range, in Will- 
zamstown, to the city of Troy, on the Hudson, by Profes- 
sor DEwey. 
Williamstown, July 4th, 1820. 
TO PROFESSOR SILLIMAN. 
Dear Sir, 
I rnrorMED you sometime ago, that I intended to contin- 
ue the Geological Section from the Taconick range, in this 
town, to the city of Troy, on the Hudson. I have before 
noticed the rocks on the roads from this place to Troy, 
North and South of the direct line, and I have lately passed 
on this line from Troy, through Brunswick, Grafton, and 
Petersburgh, over the Taconick range, to this town.— 
. Through these three towns to Troy, the distance from the 
West line of Massachusetts, is very nearly twenty miles in 
a straight line; and as the rocks are similar on the routes 
North and South of it, the geology will embrace a section 
several miles in width. It will be recollected, that the rocks 
of the Taconick range in this town, were stated to be argil- 
laceous-slate, chlorite-slate, and talcose-slate. The last pre- 
dominates, and abounds on the descent of the range into 
the valley of Petersburgh. This valley, of variable breadth, 
extends several miles North and South, and is travers- 
