On the physical geology of Tennessee. — Foerste. 345 
In conclusion, then, I wish to call attention to the following 
points : ( 1 ) Previous to the last deposition of sediments the 
country had much deeper drainage-channels than at present. 
( 2 ) The time of the making of the gravel and the sand being 
coincident with a period of increasing humidity, changes of the 
water-level may have caused minor local unconformities between 
deposits that are closely consecutive in time. ( 3 ) The volcanic 
dust was not deposited in waters forming one great lake in this 
region. ( 4 ) The fauna of the Equus beds and that of the Me- 
galonyx beds must have been, at least to some extent, contempo- 
raneous *. 
Augustana College, Rock Island, 111. 
ON THE PHYSICAL GEOLOGY OF TENNESSEE AND 
ADJOINING DISTRICTS IN THE UNITED 
STATES OF AMERICA. 
By Dr. Edward Hull.+ 
WITH NOTES AND COMMENTS. 
By Aug. F. Foerste, Cambridge, Mass. 
The Unaka Kange, on the boundary of Tennessee, is composed 
chiefly of granite, gneiss, and crystalline schists, presumably of 
Archaean age, and forming a prolongation of Prof. Dana's • • Ar- 
* This statement is based on the authority of professor Cope, who has 
determined the age of the deposits from the fossils named above, and 
who published a figure of the Megalonyx skull in American Naturalist 
Vol. XXIII, PL XXXI. The statement made by him in the same place, 
that the skull was "found in the Ticholeptus beds of Kansas" was a 
lapsus calami afterwards corrected by himself. In a letter to me writ- 
ten a year before the publication of this number of the Naturalist, he 
. gives the age of the fossils as Plistocene. The occurrence of E. major 
and Megalonyx in the same gravel seems to verify professor Cope's sup- 
position that the Equus beds run into the Plistocene, when he says 
{ Tertiary Vertebrata, p. 4.): "A probably continuous succession of 
lakes has existed from this period ( Loup Fork) to the present time in 
ever-diminishing numbers ;" and it also bears out his guess that, "this 
fauna ( Equus ) was probably contemporaneous with that which roamed 
through the forest of the eastern portion of the continent, whose re- 
mains are enclosed in the deposits of the caves excavated from the an- 
cient limestones." The recent discovery of Megalonyx in undoubted 
Plistocene deposits in Ohio, the character of the molluscan remains 
taken from the clay above described, and the evidence of ice-action in 
the sand, supports Gilbert's argument that fie Equus fauna must be 
referred to the Plistocene Time division (Lake Bonneville, p. 3 '. > 7 ) : and 
the " old " character of the topography of these beds in Kansas may 
perhaps help to explain the difference discussed by this same author 
( p. 401 ), between the physical and the biotic evidence relative to the 
age of the Equus beds. 
t London Quarterly Journal. February. 1891. 
