White Limestones of Sussex County, X. J. — Xason. 161 
in which the English chalk was deposited was probably deeper 
than the Niobrara sea between the present site of Yankton 
and the eastern shore, somewhere near the middle of Iowa. 
Neither sea was necessarily very deep. As to our Sioux river 
area of deposition I conceive that the lands draining into it 
had subsided practically to base level, and that therefore 
chalk may have been deposited within a few miles of shore. 
The singular absence of corals, sea-urchins, and all the higher 
forms of marine invertebrate life, except one species of Ino- 
ceramus and one of Ostrea, requires explanation, but at 
present there is none to offer. The seas of the English chalk 
were somewhat richer in respect to such types of life than 
ours; but, compared with many other seas, their striking 
poverty in all but lowly organized microscopic forms must be 
acknowledged. 
The practical identity of conditions in the two widely sep- 
arated regions we have been comparing remains a fact of 
much scientific interest. While, in the forms of coccospheres 
and Foraminifera, the lowly and the obscure of earth's or- 
ganic hosts were revelling in peaceful and unpolluted seas in 
the longitude of the first meridian and contributing their 
dead skeletons to form the chalk of Europe, far away to the 
west, beyond the 90th meridian, more than a quarter of the 
waj^ around the globe and separated from the first area by an 
abysmal ocean and a continental mass of land, there was 
another clear sea with low flat shores in which the same or 
very similar humble types of life were contributing material 
to form the chalk beds of Iowa, South Dakota and Nebraska. 
SUMMARY OF FACTS PROVING THE CAMBRIAN 
AGE OF THE WHITE LIMESTONES OF SUS- 
SEX COUNTY, NEW JERSEY. 
By Frank 1.. Nason, New Brunswii k, V I 
In the prolongation of the Appalachian system through 
northern New Jersey, eastern New York and beyond, there 
exist areas, some portions of which are white, highly crystal- 
line limestones, while others arc blue and inor.e or less unal- 
tered; the former have generally been assumed to be of 
