Notice of a singular Conglomerate, &c. 245 
of mica slate, hornblende slate and granite. The enquiry 
then arose, must not this conglomerate belong to a prim- 
itive series ? . . 
The present season I have discovered this rock in nu- 
merous bowlders on the west side of Hoosack Mountain. 
_ These are most numerous half a mile. or a mile, west of 
Windsor meeting-house, only two or three hundred feet 
below the top of the mountain, and, without doubt, many 
miles from any secondary region. ‘The number and size 
of these loose masses (some of them 6 or 8 feet in diame- 
ter,) preclude the idea of their having been removed very 
far from their original bed. But I had no opportunity of 
searching for the rock in situ. The rock in the vicinity is 
gneiss and mica slate, succeeded, a few miles west, by 
granular limestone ; and I have no doubt this conglomerate 
will be found associated, in some way or other, with this 
series. 
I send a specimen of this singular rock with this notice, 
with the request, that if I have mistaken its character, or 
if it is already described in any geological treatise, you will 
not admit this communication into the Journal. I have 
not at this time an opportunity to consult all the most recent 
geological publications of Europeans. 
Flint ? | send also a specimen having the conchoidal 
fracture and grayish black colour of flint. I found it in 
bituminous shale of the coal formation, in West Springfield, 
on the bank of Agawam river; to which locality I was 
conducted by Mr. H. Herrick, of New-Haven. From 
appearances I conjectured that this mineral had formed 
around a branching zoophyte. If it be not flint, it is a 
hornstone approaching very near to it. 
Trap Tuff.—In the 6 vol. of the Journal of Science, I 
have given some account of this rock, from a hasty exam- 
ination of it; and I am now able, from a re-examination, to 
corroborate the suggestions there made, and to add a few 
more remarks. It exists on the east side of Mount Tom in 
the easterly part of Northampton and East Hampton, in an 
extensive bed, between a red slaty rock of the coal forma- 
tion and greenstone. I traced it four or five miles, and 
towards its southern extremity, I had an opportunity of 
seeing distinctly the junction of the tuff with the slate ; the 
latter mounting up on the back of the former at an angle 
