562 EXTINCT TORTOISES 
the earthquake in the case in question was not progressive at all, but that 
it was produced by some force within the earth, acting outward. 
Professor ANDREWS stated that he had observed the earthquake at Co- 
lumbus, Ohio, and was struck by the fact that the motion, instead of being 
a sudden shock or jar, as is commonly the case, was like the gentle undu- 
lation of a boat in the water. He thought if the ear on mad been the 
result of a sudden IOR directly beneath, there would have been a 
sudden jar instead of this undulatory motion. It e possibly be ac- 
counted for by the fact that there is a blanket of cog shies from eighty 
to one hundred feet in thickness eran tne Columbus, which might serve 
to break the force of the concussio 
Professor WINCHELL thought iiè suggestion of Professor Andrews 
would be applicable to the sharon in connection with this earthquake, 
if those phenomena had not had an existence over so wide an area. It 
seemed incredible that pai like an arthquake wave should have 
been transmitted from any superficial piires along the earth’s surface 
with BeA like te rapidity that was indicated. 
There must have been a deep-seated force exerted, the results of which 
achat iis surface at remote points nearly at the same time. It would 
m to indicate that the seat of earthquake activities is at some point 
ota e earth, far removed from its surface. He thought evidence 
might possibly be found in this phenomenon, tending to corroborate the 
theory of some geologists in reference to the fluid condition of the earth’s 
interior, and the comparative thinness of the solid crust upon which the 
mountains have been reared. 
On THE Extinct TORTOISES OF THE CRETACEOUS or New JERSEY. 
By Proressor E. D. Core. 
His object was to explain two cases of “ generalized groups,” 
such as are not common, comparatively speaking, and are of much 
importance in the history of life. Generalized or synthetic groups 
of naturalists were explained to be those which combined the 
characters of others. They were generally found in earlier geo- 
logic time, while the more widely differing groups occurred later 
in time. The cases were as follows. It was explained that the 
existing division of the marine turtles (Chelontide) possess ster- 
nal bones united by but few sutures, or with wide intervals; 
straight humerus and femur, and flat limbs, with truncate finger- 
bones incapable of flexion. It was shown that the existing 
snapping tortoises possess a narrow cross-shaped. sternum with 
the bones everywhere united to each other, the femur and humerus 
curved, and the toes with hinge-jointed phalanges capable of much 
flexion. It was then pointed out that in the New Jersey Green 
