244 Notice of a singular Conglomerate, 4c. 
Chrysoprase. 
| have lately received from Gen. Field,* of New-Fane, 
Vt., specimens of this mineral found in that town associa~ 
ted with serpentine. It closely resembles the chrysoprase 
fom eager Silesia. 
Art. Vil.—Notice of a singular conglomerate, and of an 
tn locality of trap tuff or tufa, in a letter to the 
Editor 
sus 
Ticeavs brad rete years in My possession a specimen 
ofa very singular a rock, which |] found as a 
rolled mass on the banks of Deerfield river, and of which, 
T have never met witha Aeon It may be described, 
as a mica slate, in whichare imbedded numerous rounded peb- 
bles of limpid quartz. 'Uhese vary in diameter from one 
quarter of ap inch, to two inches ; and their colour is light 
gray, or milky, and, in some instances, especially in the 
smaller nodules, they have a strong resemblance to semi- 
opal. They are in general perfectly rounded, may be dis- 
engaged from their bed. and appear precisely Ake quartz 
oaies that are found along the banks of riv They 
constitute, in grees one half of the rock, Boa in no 1n- 
stance, (although I have recently seen numerous specimens,) 
have I discovered a pebble of any other sort. base 
of the rock has a schistose structure; but I have not no- 
ticed any thing like planes of stratification. The mica is 
abundant, though in small plates ; and the quartz is gran- 
ular, and may be merely comminuted portions of the im- 
bedded nodules, 
It was — act the peculiar composition of this con- 
glomerate tracted my attention ; but its locality also. 
Deertield A we in‘all its course before it reaches the spot 
where I found this rock, does not pass over, or n ear, aby 
secondary rocks. Its bed is entirely primitive, consisting 
* Seo Gen Pi014° at th * +1. } were | 
wa seeatindees ~ 9 
