4 TRIASSIC FISHES AND PLANTS. 
land mentioned above and spread round its margins—were laid down during 
the last half of the Triassic age, and a subsequent subsidence caused these 
to be covered by finer and more calcareous sediments during the last half of 
the Cretaceous age. 
With the Mesozoic deposits of the interior of the continent we have now 
no immediate concern, as the task before us is to trace the history of those 
which accumulated on its eastern slope, and especially those formed during 
the Triassic age, viz: the shales, sandstones, and conglomerates, which were 
deposited in the lakes and bays already referred to. Of these Triassic areas 
the most northerly is that of Nova Scotia, about the Bay of Fundy, Prince 
Edward Island, ete. The second is that of the Connecticut Valley, which 
reaches from the north line of Massachusetts to Long Island Sound. The 
third, which may be called the Palisade area, extends from Rockland County, 
N. Y., to Orange County, Va., a distance of about three hundred and fifty 
miles. This area, which has the form of a long and narrow trough, is 
bounded on the west by the Blue Ridge, and on the east by the Archean 
rocks of the Staten Island, Trenton, and Philadelphia axis. 
In Virginia and North Carolina are several distinct and smaller basins 
lying eastward of the Palisade area, some of which contain coal beds of 
economic value. The Triassic rocks which fill these basins are alike in 
this, that they consist chiefly of beds of conglomerate, sandstone (sometimes 
arkose), and shales, interstratified with heavy beds of diabase. The pre- 
vailing color of both sandstones and shales is red or reddish, but the Con- 
necticut. area includes layers of nearly black shale charged with carbona- 
ceous matter, containing many remains of fishes and plants, and even some 
thin films of coal. Also a small part of the series in New Jersey consists of 
dark or dove colored shales charged with organic matter, sometimes crowded 
with the remains of fishes, and exhaling a marked bituminous odor when 
struck with a hammer. It should also be said that a small detached basin 
of Triassic rocks in Southbury, Conn., includes a thin sheet of impure lime- 
stone. 
The sandstones of the series are frequently firm and massive, and are 
extensively used as building stone, important quarries having been for many 
years worked at Long Meadow, Mass., Portland, Conn., and Newark, N. J. 
"Ae. 
4 
