362 _ The American Naturatst. [Apeil, 
remains of the former bottom of the lake. Furthermore, such com- 
parative studies of this material as a whole is enhanced by the discov- 
ery of other relics found commingled with it. Of this Professor Cope 
has said that ‘‘Scattered everywhere in the deposit were the obsidian 
implements of human manufacture. Some of these were of inferior, 
others of superior workmanship, and many of them were covered with 
a patine of no great thickness, which completely replaced the natural 
lustre of the surface. Other specimens were as bright as when first 
made. e abundance of these flints was remarkable, and suggested 
that they had been shot at the game, both winged and otherwise, that 
had in former times frequented the lake. Their general absence from 
the soil of the surrounding region added strength to this supposition. 
Of course it was impossible to prove the contemporaneity of the flints 
with animals with whose bones they were mingled, under the circum- 
stances of the mobility of the stratum in which they all occurred. 
But had they been other than human flints, no question as to their 
contemporaneity would have arisen. . . . . . . . The probability of 
the association is, however, greatly increased by the discovery, by Mr. 
Wm. Taylor, of paleolithic flints in beds of corresponding age, on the 
San Diego Creek, Texas.” 3 
Should, in the future, sufficient evidence come to light to establish 
any such theory as this, then there will indeed be opened to us another 
important and interesting chapter upon the paleontologic history of 
man.—R. W. SHUFELDT, Takoma Park, D. C. i 
Flora of the Great Falls Coal Field, Montana.—Prof. J. S. 
Newberry gives an interesting account of this flora in the American | 
Journal of Science, XLI., March, 1891. A number of specimens — 
were submitted to him for examination, which he found without — 
exception to be species described by Sir Wm. Dawson from the Koo- 
tanie Group, Canada, or by Prof. Heer from the Kome Group, Green- 
land. Further examination by Prof. Fontaine showed them to ei 
also identical with fossils of the Potomac formation. This proves con 
clusively the general identity of the geological horizons of these al ae 
groups, and confirms the view that the Potomac group is Lower Cress 
ceous, and not Jurassic. A comparison with the Old World forme 
leads Prof. Newberry to assert that the Potomac, the Kootanie, and the a 
Kome groups represent perhaps distinct but closely related epochs 0 a 
the Neocomian or Lower Cretaceous of the Old World. a 
The paper closes with a brief description of the new specs: — 
Chiropteris williamsii, Chiropteris spatulata, Zamites apertus, Barre — 
* AMERICAN NATURALIST, Nov., 1889, PP. 979, 980 
