Geology and Natural History. 221 
poses of research, Keenig’s apparatus may be all that is desired. 
But for illustration in class roo ms, and especially to large num- 
bers, the new arrangement just described will be found to possess 
great advantages. 
IL GroLtocy AND NATURAL HIsTory. 
New Order of Eocene Mammals.—At the last meeting of the 
Shiites Academy, Feb. 17th, Nebo’ O. C. Mars made a 
communication on a new order 0 ne Mammals, for which he 
proposed the name Tillodontia. These animals are among the 
Ungulates, and Rodents. In Tillotherium Marsh, the type of the 
order, the skull has the same general form as in the ears, but in 
its structure resembles ae of Vinegaltets The molar teeth are of 
the ungulate type, the canines are small, and in each jaw Shete is is 
a pair of large scalpiform in ncisors fae with enamel, and grow 
ing from persistent pulps, as in Rodents. The adult dentition is 
as follows :—Incisors cy canines —; premolars —; molars aS 
The ned ea of the lower jaw with the skull corresponds to 
that in Ungulates, The posterior nares open behind the last upper 
molars. — brain was small, and somewhat convoluted. The 
at i h 
genera of this order are less oo but all fat arentl y had the 
Same general characters. There are two distinct families, Zidlo- 
theride,* in which the large ine g rrr rer pulps, 
the teeth are rootless. Some of the animals of this group were 
as large asa Tapir. With Hyrax et zt Toxodontia the present 
order appears to have no near aftini 
2. On the alleged parallelism oF ‘Coal beds ; by J. J. Sreven- 
son. (Proc. Amer. Phil. Soc., xiv, 283. )—Mr. Stevenson in this 
paper gives examples, from this country and England, of the sub- 
division of coal be ~ and of variations in the thickness of the 
intervening rock strata. The interval between the oe oh Free- 
rt and te coal beds along Yellow Creek in Ohio varies 
— “i 160 a in ese miles. e same interval on Wells 
ries in one mile from 8 feet to 28, and from this it en- 
rene heyond [distance na not stated] to 110 feet. In = sections 
given by P his Pennsylvania Report the intervals 
are 184, 143, 142, hr, 109, 103. The total interval ‘rane se 
Pittsburgh coal bed and the Upper Freeport varies in Ohio 
* This family may possibly prove to be identical with Anchippodontide. 
