1893. ] NEW YORK ACADEMY OF SCIENCES. ig 
the floceulent, light-brown material, containing fragments of 
other tests. The trilobites are preserved either in calcite or the 
brown phosphate, with usually a dark line or band at the edges, 
to which, doubtless, is due the black, shining surface which 
they show when broken out of the rock. 
The foraminifera are many chambered, with the cells grouped 
apparently much like Globigerina; but they are not perfect 
enough to determine exactly. The smaller bodies referred to 
Monadites are numerous, and of three forms—round or oval, 
pear-shaped, and urn-shaped. They sometimes have two 
chambers, and rarely three. They show very often, long, 
straight or curved, slender spines, and also what seem to be 
stems on which they grew. (The spines very probably repre- 
sent the whip of the flagellate infusoria, to which sponge- 
gemmules have been referred. ) 
Towards the surface of the nodule, the brown phosphate 
becomes more dense, and an opaque ring sharply separates it 
from its matrix. Sometimes the central part is darker, and 
separated from the outer zone by a similar dark ring; or it 
may be distinct on one side, and fade out into the lighter part 
on the other. 
The matrix may be of the same phosphatic material, but is 
more generally of glauconite grains, mixed with small angular 
fragments of quartz. Its coarseness then contrasts strongly 
with the fine grain of the phosphate. The glauconite is in 
irregular masses, averaging 75" in diameter, and often appearing 
as if made up of a number of small coalescing grains. Smaller 
round or oval grains are also common. 
The gray sandy layers are composed of small grains of quartz 
and plates of mica, the latter almost always lying in the plane 
of bedding. In the fine shale there is an abundant groundmass, 
probably argillaceous, and comparatively few of the larger 
fragments. 
The nodules from Zone 3 are rather different from those of 
Zone 2, and show considerable variety in structure. The mass 
of the sandstone is made up of angular fragments of quartz, 
and more rounded ones of calcite, with a fine dark-colored 
cement, more or less ferruginous. Near the nodules, grains of 
glauconite almost entirely replace the quartz, the calcite still 
being abundant. Sometimes each grain is coated with a thin 
dark layer of phosphate, and the cement is largely or entirely 
the flocculent phosphate. 
The nodules themselves are much less pure than those of 
Zone 2, and contain much foreign material, mostly minute plates 
and shreds of mica. The large grains of quartx and calcite, 
