EF’. Hitchcock, Jr., ona new species of Clathropteris. 23 
formation which Elie De Beaumont considers as ah belong- 
ing to the lias; and at Pouilly in Auxois, by s. Bonnard 
tion ; both of which go to prove that this plant is one of the most 
important characteristics of the lias, and it is probable that it 
will appeat again in more localities where this formation exhibits 
itself.” 
latter sandstone formation however (that of the Youu) as it ap- 
pears belongs to the keuper, in which Alberti again notices this 
fern in Neuen Welt near Basle.”’+ 
In 1849, in his Index Paleontologicus, Bronn places the Cla- 
thropteris both in the Lias and the Keuper.t 
*"W. Granite. Sandstone. Trap. Sandstone. , Granite. E. 
a, Sonthampton hes mine ; “ sy hampton Seminary ; c, locality of Clathropteris; d, 
Mt. Tom; e, rt of foot-m ah de Connecticut river; g. Mt. Holyoke Seminary ; h, 
Hadle y; 2, Gra j, Roe “ie ; 
The cai of East Hampton is found in a coarse reddish 
sandstone, on the west face of Mt. Tom. The upper part of this 
mountain is trap, beneath which the sandstone crops out with 
an easterly dip of about 25°. The sandstone has a _ southeast- 
erly oe across the whole of the Connecticut valley. That east 
of the trap range is made up of finer materials, and is of a more 
slaty character than that on the west. Bassett’s s Quarry, where this 
ern occurs is somewhat west of the middle of the valley, as may 
be seen in the annexed section. In this section lately measured 
my father—Dr. Hitchcock of Amherst College—it is found 
that the thickness of the oe east of Mt. Tom is more than 
8,000 feet, and that on the west, or below Mt. Tom is near! 
5,000 feet. Supposing one half of this thickness to be accounted 
for by pb deposition on an inclined surface, there will still 
remain a thickness of some thousands of feet both above and be- 
low the locality of the fern. A thickness equally great for the 
ore of the Connecticut valley in measuring another sec- 
Brongn. Veg. Foss., p. 131 and 132. Lethea Geognosti 
: Index Paliont., vol. ii, p. 22. t ostica, vol. i, p. 140. 
