1880. ] of the Atlantic States. 7X1 
The absence in the Triassic rocks of the peculiar markings that 
are made in soft mud when it freezes, and which are as capable of 
being preserved as are rain-drop impressions or footprints, is 
another although a negative indication that there was a mild 
climate in the Eastern States during the Triassic period. 
Then, too, there was not a “ paucity of animal life” in Triassic 
days, as thousands of footprints show; the waters of the estuary 
were also inhabited by immense numbers of fishes, some of them 
of considerable size. As to the absence of molluscan life owing 
to the coldness of the waters, we know that many species of 
Arctic shells are found in the mud at the foot of the glaciers that 
terminate in the sea in high latitudes, and that the same and 
allied species are found in the glacial clays both of Europe and 
America, thus showing that the presence of ice could not account 
for the absence of molluscan remains in the Triassic formation. 
The absence of shells in these rocks seems due to the fact, 
long since pointed out by Sir H. De la Beche,! that animals 
which live on the sea bottom cannot exist upon a bottom of red 
mud, and that the presence of peroxide of iron in the waters is 
fatal to animal life ; the presence of peroxide of iron in the rocks 
will also promote the rapid decomposition of such organic 
remains.as may become imbedded in them. All who have wan- 
dered along the shores of the Bay of Fundy, where the bottom 
is composed cf red mud, will remember how destitute they are in 
mollusks, radiates and crustaceans, the * waters are inhabited, 
however, by great numbers of fishes, belonging, I believe, to a 
limited number of species. Thus in almost every particular, the 
_ Study of the present condition of the Bay of Fundy furnishes us 
with the key with which to unlock the ONY of the Triassic 
formation. 
The information added by the papers of Mr. Heinrich and 
Prof. Fontaine, tends to confirm the conclusion that the Triassic 
rocks in the Atlantic States were formed in one estuary, in the 
northern end of which sandstone and shales were ‘deposited, 
being subjected toa greater subsidence than the southern ex- 
tremity, where the shores were low and favorable for the accumu- 
lation of carbonaceous mud and peat. 
As the determination of the age of the rocks in question from 
the fossil plants they contain, has led to widely varying results, 
‘Memoirs of the Geological Survey of Great Britain, Vol. t, p. 51. 
