Remarks on Bowlders. R17 
Berzelius mentions the action of lithia, on platina foil, aS 
characteristic, but Ihave not yet made“this trial. As our 
mineralogists have pronounced it petalite, I feel inclined to 
. 
submit it to a regular analysis. 
ART. I.—Remarks on Bowlders. By Peter Dossoy. 
TO PROFESSOR SILLIMAN. 
Sir, =i F ‘ 
I have had occasion to dig up a great number of bowlders, 
of red sandstone, and of the conglomerate kind, in erecting a 
cotton manufactory ; and it was not uncommon to find them 
worn smooth on the under side, as if done by their having 
been dragged over rocks and gravelly earth, in one steady 
position. On examination, they exhibit scratches and fur- 
rows on the abraded part; and if among the minerals com- 
posing the rock, there happened to be pebbles of feldspar, or 
quartz, (which was not uncommon,) they usually appeared 
not to be worn so much as the rest of the stone, preserving 
their more tender parts ina ridge, extending some inches. 
When several of these pebbles happen to be in one block, 
the preserved ridgés were on the same side of the pebbles, 
so that it is easy to determine which part of the stone moved 
forward, in the act of wearing. 
I have caused blocks, with the above appearances, and 
weighing 15 tons, to be split up; and there are now a num- 
ber of good specimens about the place, that will weigh from 
10 to 50 cwt., dug out of the earth, 200 feet above the stream 
of water in the vicinity. z 
These bowlders are found,*not only on the™surface, but J 
have discovered them a number of feet sap in the earth, in 
the hard compound of clay, sand, and gre \ 
One block of more than 30 cwt., marked and worn as above 
described, was dug out of a well, at the depth of 24 feet: a 
part of which is still to be seen. e 
: 2. 28 
