246° Notes on American Geology. 
are so much more remote-from the axis of elevation than the ter- 
tiary shells of New York, that the uplift of the Rocky Mountains - 
must have been far greater a the upper tertiary period than 
was any part of the Atlantic c 
I know not what reason can’ = given for considering the wisoh 
of the transition as one group, as Mr. Rogers has done, when 
with very few exceptions the inhabitants of the seas have been 
destroyed and new creatures succeeded at five distinct epochs, 
and one of these groups is no more to be compared with another, 
than’is the oolite with the green ‘sand formation’; yet each of 
these belongs to a different group in all the systems of geology 
hitherto published. The term, lower secondary, applied by the 
same geologist to the transition system, is equally iAgeeitionstle, 
as it has scarcely a single feature in common with what has . 
erto been termed secondary by all other geologists, and rabies 
an order, not a single series of strata linked together by palzon- 
tological affinities. The term, lower secondary, would be far 
‘More appropriately given to. the strata comprising the magnesian 
limestone, lias, oolite, &c..as upper secondary has. been Acosieg 
used. to designate the cretaceous group. 
Organic Remains of the Transition. - 
No remains of reptiles, nor any impressions of the feet of birds 
or of reptiles, have been found in any of the trilobite rocks of the 
United States ; but fucoids or marine plants abound in the sand- 
stones, many aE which. have a digitate or trilobed form, and by 
the aid of the imagination. could ‘be readily converted into ornt- 
thichnites, or reptile trails. I am far from an intention to discredit 
the science established by Professor Hitchcock, as. his descrip- 
tions apply to more recent strata than the transition, and which I 
have never studied, and his arguments are too ingenious for me. 
to doubt ; but I must be permitted to challenge his ornithichnite, _ 
of which even he is doubtful, in the graywacke of the Hudson 
river,* one of the oldest transition rocks in New York, deposited 
at a period so early that scarcely any small islands dotted the 
boundless waste of waters, and they consisted of naked primary Z 
rocks, bearing neither herb nor animal life. 
* Mr. —— has iden maintained the existence of am ornithichnite in 
_ the graywacke of Hudson valley; he found an impression there, having some 
sigh pare OES the footmarks of the Connecticut valley, and he called this 
ichnite oe . time strong doubts whether it were a real 
footmark.—Epirors 
