Geological Survey, 195 
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, is se 
above mineral, crystallized in veins of quartz. The Pos 
fice is kept in a room of Denison’s Tavern, near ay 
small stream punmibg into the Connecticut. sae 
ee 
3. Poe of the Geoloyical Survey on the Grand Canal. 
For the Journal of Science. 
To ay SILLIMAN. 
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 mallee may not be muinteee 
esting to those who read that notice 
The first part, which comprises a description of the 
rocks is printed. It formsa 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 
ie ps se profile extending from the Atlantic, at Boston, 
It is 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 ay the Rev. Ed- 
ward seneons, at the request of Mr. V. R. 
concise view of the nomenelatune adopted i in 
the descugtions of the rocks, precedes the descriptions. 
A concise enumeration of facts s, with scarcely a sentence 
of hypothesis or theorizing, constitutes the whole body 
_* Communicated by Dr. T. D. Porter. 
