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 
sealbey river near Pickaway plains, pha Weight, 5lbs. 6 1-2 
inches from A. to r.—from 1, to1. 
No. 1, 2, A. two views of a 48 found 1 in alluvial earth , twenty- 
iwo feet nine inches, below the surface, im digging a salt well a 
the Scioto salt-works. These teeth are in the epiutt of Caleb 
Atwater, Circleville, Ohio. The latter tooth weighs nine pounds, 
though several fragments have been eres off. Its original weight 
was probably from 12 to 14 lbs. at lea 
Arr. VI. be Sai section from Taconick range, in Will- 
oe Dias to the city of Troy, on the Hudson, by Profes- 
sor Dewey. 
Williamstown, July 4th, 1820. 
ae TO PROFESSOR SILLIMAN. 
Dear Sir, | ! 
I ivrormep 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 thetroads from this place to. Troy; 
North and South of the direct line, and I have lately passed 
on this line from Troy, through Brunswick, rat, and 
Petersburgh, over the Taconick range, to this town.— 
Through these three towns to Troy, the distance foot the 
est line o f Massachusetts, i is very nearly twenty miles in 
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 ito 
the valley of Petersburgh. This valley, of variable breadth, 
extends ‘several miles North and South, and is travers- 
