122 
March 16th. Geological Section. 
Pres. NEWBERRY in the chair. ‘Twenty-six persons present. 
Dr. FEUCHTWANGER made some remarks on the recent 
low prices of diamonds, and read from lately published price- 
lists in illustration. 
THE PRESIDENT presented an extended discussion, accom- 
panied with a series of charts, “On Circles of Deposition in 
Secondary Sedimentary Rocks, American and Foreign.” 
In this account Dr. Newberry described the application to 
these later formations, of the views presented by him at the 
Portland meeting of the American Association for the Ad- 
vancement of Science, 1873, and published in the proceedings 
thereof; and also set forth, with especial reference to the 
Paleozoic rocks, in Vol. I of the Final Report of the Ohio 
Geological Survey. 
The first conception of this theory had been derived by 
him from the succession of Cretaceous beds, as studied in 
their great developement in the far South-West, between the 
Colorado River and the eastern part of Kansas and Texas. 
Everywhere he had found the lowest member to be a heavy 
sandstone and conglomerate, full of fossil wood and angio- 
spermous leaves, so abundant and well preserved as to prove 
that they had not been carried far from their original place 
of growth. Over this series (equivalent to No. 1 of Meek 
and Hayden) comes a great limestone, rich in marine fossils 
(Nos. 2 and 8, M. and H.); and this in turn is overlaid by 
a double series, first of limestones, and then of clays, shales 
and mixed sediments, together corresponding to Nos. 4 and 
5 of the Upper Missouri rocks. The record is simple and 
clear,—a great submergence of the Triassic land beneath the 
waves of a gradually-encroaching sea. Such a sea lays down, 
of necessity, first, a great sheet of fragmental beds, formed 
from the wear of the land, and containing the remains of the 
vegetation that clothed that land; then, if the sea continues 
to advance, this formation of beach-deposits will be carried 
farther and farther inland, while, as the water grows deeper, 
they will be followed, over what was previously the shore 
region, by the lime-deposits of clear, open seas, with the 
shells, ete, that there occur. The third series, shales and 
mixed sediments, represents the gradual withdrawal of the 
sea, and the concluding stage of the great cycle of deposits. 
