Middiciown Minerals. 907 
Mr. Williams, is the gorge where the Connecticut river, 
leaving the secondary, breaks through the primitive ridges, 
which are from this spot uninterruptedly continued to the fa- 
mous locality of crysobery!, bery], &c. at Haddam, which is 
only a few miles below, and belongs to the same geological 
formation. This region is famous for large beryls. One of 
those transmitted by Mr. Williams, is two and a half inches in 
the diagonal diameter, andis a well formed crystal. 
Some of the rubellites are half an inch in diameter, the 
crystals are distinct, and the colour lively and delicate. A 
group forwarded me by another gentleman for inspection, and 
to be returned, is singularly rich. It is situated in a mass of 
granite,and covers a space of about four inches on each side. 
‘This space is filled with crystals of rubellite, laterally agere- 
gated like columns of basalt, or like the columnar argillaceous 
iron Ore; there appear to be forty or fifty of them, and they 
are as distinct as erystals so closely compressed usually are. 
In the midst of them there lies a large erystal of the size of a 
thumb, of a dark leek green which much resembles sahlite, 
but as there is in another part of the stone a large crystal of 
rubellite, containing a distinct crystal of the green substance, 
perfectly threaded, longitudinally through it, in the manner 
of the Chesterfield tourmaline, although in the reverse or- 
der, it appears probable that the green crystals are tourma- 
line. 
We trust that every attention will be given to this new and 
interesting locality. 
P.S. October 15,1825. The fol’ wing information has just beem 
received from Mr. Williams, in a letter dated 
Mippietown, Oct. 12th, 1826. 
Iam happy to inform you that I have discovered rubel- 
lite, beryl, &c. in place. The rock in which they are 
situated is two anda half miles south-east from the city, and 
forms part of the primitive region, which crosses the Con- 
necticut river atthe narrows. The rubellite is found ina bed 
of granite, where it is associated with green tourmaline in a 
vein of quartzand feldspar traversing the granite. The green 
tourmaline is frequently inclosed in the red, the sides and an- 
gles of both prisms corresponding : a crystal of this kind, which 
I saw, but. was unable to detach. from. the rock, measured 
three quarters of an inch in diameter. The-same. granite 
