an 
Geological Survey. ig 
7, Sillimanite.* 
- On the same turnpike, not far from two and a half miles 
beyond this, in the parish of Chester, on the left hand of 
the path, ina flat rock, which is chiefly mica-slate, I be- 
lieve lying a few rods south of the Post Office, 1s the 
above mineral, crystallized in veins of quartz. The Post 
Office is kept in a room of Denison’s Tavern, near a 
small stream running into the Connecticut. ' 
8. Progress of the Geological Survey on the Grand Canal. 
For the Journal of Science. 
“To Pror. Sitnuiman. 
You having given notice of Mr. Van Rensselaer’s in- 
tended geological survey of the Erie canal line ;—a short 
account of the progress already made, may not be uninter- 
esting to those who read that notice. 
The first part, which comprises a description of the 
rocks is printed. It forms a thin octavo volume of 163 
pages. But the engravings will not be completed until 
about the middle of April. One of the plates exhibits a 
geological profile extending from the Atlantic, at Boston, 
to Lake Erie. Itis four anda half feet long, embracing 
nine degrees of longitude, and running near the 43d de- 
gree of north latitude. It is engraved by excellent ar- 
tists, Messrs. Rawdon and Clarke, at the expense of $530. 
The other presents a profile of rocks from the western 
part of Massachusetts to Boston, drawn by the Rev. Ed- 
ward Hitchcock, at the request of Mr. V. R. 
A very concise view of the nomenclature adopted in 
the descriptions of the rocks, precedes the descriptions. 
A concise enumeration of facts, with scarcely a sentence 
of hypothesis or theorizing, constitutes the whole body 
* Communicated by Dr. T. D. Porter. 
