The New York herald., 1851-08-26

. copgomerate bed or beds are generally met with
at the base, and the OVERLAPPING sandstones are prn-
cipaly hne-grained and purely quartzne, but fur
ther west, partially calcareous bands are found in
terstratifed. The rock is sonett mes Strongly
impreg gnated, over limited areas, with oxyd
of iron, which is occasionally found in their
seams or beds, in pure state, as red hemltue'
MIR. Hunt explained these by reference to the FER
ruginous springs, which are still found issuing
from the crystalline rocks, aud which often cemsni
large are Of gravel with the deposited oxyd, ana
sometimes form beds of limenite and iron ochre
On Lake Huron, the floor upon which the siluvian
rocks were deposited is about POO feet higher thau
upon the ST. Lawrence; aud at Matchedosh Bay,
the formation ia question is represented by very
small thickness OF greensh sandstone Farther
north, on the lake, about forty feet Of reddish
and greenish sandstone and m arls, quite cllcareous
towards the top; and at Sault Ste. Marie, there is
considerable mass of reddish sandstone, in soma
parts, conglomerate in character. Hitherto no
fossils in this formation has rewarded our Sc ,rch
other than those described and figured by Mr..
Hall, until year since, when the attention Of Mr.
Logan was called by Mr. r. Abraham, of Moh-
sandstone, at Beauharnais. Casts of these aud
specimens of the stone ITSELF bearing the foot prints,
were carried, last winter, by Mr. Logan, I, L,nd,n,
and submitted to the critical examination Of Pro-
fessor Owen, whose expressed opinion that they are
those of a reptile, and probably cheloniin,
is well known to the members of the association
have only to add that this season similar tracks
have been discovered in large numbers in different
is great diversity in their sze but they agree in
their general characters. The beds containing
them are lying at very small angle, and are over
laid by undoubted calcferous sandstone, containing
the es0m0nlIkatHs pniaRPutatus, aud the m1ciMeH
figured by Mr.. Hall, while to this formation sue
ceeds the Trenton limestone with its characteristic
fossils. MIR. Hunt remarked that although the dis-
covery of traces of reptile in the lowest rocks now
recognized d. to be fossferous, was new ana start
ling fact for those who have supported the idea OF
progressive deveopement, it was one for which the
progress of modern geology had, to some extent,
prepared US. He alu led to the remains OF fishes
which, about twenty years, were unknown below
the coal, but have been successfully brought down
through the Devonian upper and lower siluvian
formations The remains OF fishes are more recently
announced existing even in the Bala lime stones,
which are far down in the Cambran system of Prof.
Sedgwick, but which may be considered the aaao-
gues Of the lowest portion OF our siluvan rocks, II
we regard the Potsdam sandstone the representa-
tive OF the Dubious sandstone in Russia, and the
lowest Cambrian rocks characterized by singula
and fucoids. The rare occurrence of animal re-
mains Ia these sandstones which, in Russia and
Scandinavia, as we'll as in America, are found at
the base of the form ations hitherto recognized as
fossiferous, is, perhaps, reason why they have
hitherto been regarded as dating from the very
commencem ment of animal existence; but when We
remember that the superior sandstones Of the silu
Wan rocks, the old and new red, are almost equally
destitute Of animal remains, are inclined to look
for some other to explain their absence from
silicious deposites The remains Of vegetables are
Hot unIItQueuliy IOuuu ia duu Tue Uouy
skeletons Of fishes embamed in the bitumnou, pro-
duct of the decomposition of their integuments are
found in high state of preservation but the phe-
nomena which we have to explain is the absence Of
the calcareous coverings of mallusces and crusace
Gus. And this, think, may be accounted for by
the action of atmospheric waters charged with car
bonic acid, which are capable of taking into sou-
tion a considerable quantity of carbonate of lime:
The abrading action Of sharp silcious sand
is also to be taken into account, which,
where it does not destroy the shells, renders
them more easily affected by the solvent.
Such being the case it would only be in those beds
which either centan portion Of finely divided cal
careous matter, presented to the water in readily
soluble form, that We might expect to find the
shells escaping the dissolving action; and conform
ably to this fnd that those beds Of the Potsdam
sandstone which are somewhat calcareous, contain,
in great profuson, peculiar fossils These consi-
derations, coupled with the abundance Of fa,oidal
remains and the footmarks lately discovered, per-
NIT suppose that this lower formation was not,
after all, destitute of organic life has hitherto
been imagined And when | add, that our forth
coming report will furnish most undoubted evidence
Of the sedi nenary origin of the cry stalline lime
stones and syentic rocks which underie these sand
Stones it viii be conceded that neither the inferior
position Of the for nation, nor the paucty Of organic
remains, can be sdduced as arguments against the
suppostion that its epoch was one prolific in living
existence, and, perhaps, long subsequent to the
commencement Of life upon our planet.