222 Letters of Mr. Brongniart, with remarks. 
these, that the fish were found at Westfield, beneath argii- 
ceous sand-stone. Now, throughout this whole trap form- 
ation, copper is found—principally in the sand-stone rock 
beneath the trap. It isin the form of copper pyrites, of 
oxid of copper, of green and blue carbonat, and of native 
copper.* Many shafts have been opened for working it, and 
the Connecticut state’s prison for convicts is in the aban- 
doned pits and galleries, wrought many years ago, for cop- 
per, in the sand-stone beneath the trap, in the township of 
Granby in Connecticut. The existence of the copper then, 
in this region, fulfils another condition of resemblance be- 
tween the countries alluded to by Mr. Brongniart, and those 
in this region. We would add, that although no more fish 
have been obtained at Westfield, because the pit has long 
been filled with water, they have been found in various oth- 
er places in the same formation. Particularly at Sunder- 
nd in Massachusetts, in rocks that pass under Connecticut 
river; they were discovered by that excellent observer, Mr. 
Edward Hitchcock, who says they are very numerous. 
are found in the argillaceous sand-stone. The addi- 
‘tional interest imparted to our trap region by the remarks 
of Mr. Brongniart, with the peculiar nature of the country, 
will, we trust, induce some of our geologists to examine the 
entire formation with more scrupulous care, and to give a 
connected report of the whole. It is a feature almost un- 
ique, in American geology, and should not be allowed to re- 
taain without a complete and skilful delineation, especially 
_as the prehnite, zeolite, chabasie, analcime, laumonite, chal- 
cedony, agate, &c. which are found imbedded in the trap, 
7 an additional interest to the research ers" 
Poe some remarkable examples of very fine specimens of the latter, s¢¢ 
Vol I. pa. 55, of this Journal, and Bruce’s Journal, pa. 149; the former of 
these pieces weighed six, and the latter ninety pounds. 
