16 TRANSACTIONS OF THE [ocr. 10,. 
wide encircles the figure and covers the junction line of carapace. 
and plastron, reaching behind the neck. 
Carapace guite symmetrical, convex, elliptical, without figures. 
Plastron a transverse central plain band 8 in. wide, with trans- 
verse open space before and behind, } in. wide, exposing the 
whole cavity and under surface of the carapace, which 1s studded 
with small prominences, as if left in casting. 
The four legs are variously figured, and the two hind ones 
have, in a line near the body, three small round points. 
The head is as if supported by two ligamenta (?)4in. wide, 
in three bands each, the inner one with 15 small triangular per- 
forations on outer curved line. These are attached on right 
and left of carapace, and curve down and out over forelegs in a. 
circle and a half, to the carapace in front. 
On anterior plastron, right and left, at the insertion of the 
legs, are two eye-bolts, through which, with a cord, the turtle 
can be suspended if worn as an ornament or amulet. 
Pror. HUBBARD also exhibited a specimen of claystone from 
a railroad cut at Sharon, Vt., which presented a striking imita- 
tion of the form of a small turtle of 1} in. diameter. 
The PRESIDENT exhibited specimens of eruptive rocks from: 
the base of Mt. Beckwith, Colorado, a quartz-mica-diorite, with. 
crystals of sanidine and moonstone. 
Mr. F. J. H. MERRILL read a paper entitled 
NOTES ON THE AGE OF THE LIMESTONES OF WESTCHESTER 
CO., NEW YORK. 
The paper was discussed by Dr. Britton and PRESIDENT 
NEWBERRY. 
Pror. D. 8. Martin presented the following notice of 
THE ‘‘ FIELD OF ROCKS.” 
About eleven miles west of Philadelphia, on the main line of 
the Pennsylvania Railroad to Pittsburg, there occurs a most re- 
markable isolated deposit of large boulders, presenting a very pe- 
culiar problem to the geologist, inasmuch as the locality is far 
to the south of the well-determined line of the Great Terminal 
Moraine. 
