J. D, Dana—Helderberg rocks in the Connecticut Vall-y. 345 
same in age with the Bernardston quartzite. Prof. Hitchcock 
observed that the staurolitic slate, quartzite and hornblende 
rocks were just those of his Coés group in New Hampshire, a 
formation that covers a narrow band east of the Connecticut 
River from Massachusetts to Northern New Hampshire We 
crossed the river together, and saw these rocks in Northfield, 
Mass., and Hinsdale, New Hampshire. It was evident that the 
South Vernon rocks were Coés, whether the Bernardston were 
so or not. 
The characteristics of the Cods group, as given in Prof. Hitch- 
cock’s Annual Report for 1869, are, “the presence of quartzite, 
staurolitic rocks, mica schists, hornblende schists, peak gneiss, 
protogine and other rocks, lying west of the White Mountain 
series and east of the Connecticut River, along the whole of 
western New Hampshire,” besides argillaceous slates, whetstone, 
mica schists, grits, etc., of Cods Co., etc. The occurrence of beds 
of limestone at intervals is mentioned in the Report of 1870.* 
The facts observed in the region at that visit made it evident 
that the relation as to age of the Bernardston and South Vernon 
quartzites was a subject of great interest, especially in connection 
with New Hampshire geology. Prof. Hitchcock appreciated it, 
and expressed his intention of soon having the South Vernon 
tegion—for the investigation of which he had a kind of pmor 
night—carefully studied. 
ae (2 passed without anything being accomplished, 
owing, as he informed me, to the demands on his time made by 
ane, showed in some places the strike N. 15° E. and a dip of 
Staurolitic clay slate, with the same eastward dip. ‘he horn- 
bl 
*In Prof. Hitchcock’ the Cods group are 
: ‘heock’s Report for 1870, four sections across the gr 
given. In the description of that through Lyme there is the entry 2200 feet of 
Li “tvegge and limestone ; that through Orford, 100 feet of limestone ; that ~— 
“502, 50 to 100 feet of limestone. It is stated that “ mineralogically the schi 
: : : : i ther 
Wes” are mentioned as 4,500 feet thick in one section and 3,078 in another, 
*vidently the same rock essentially that occurs at Bernardston and in Vernon. 
. 
