History of lake Agassiz. — Upham. 231 
low the level of the Red river, of sheets of turf, many frag- 
ments of decajdng wood, and a log a foot in diameter at G-lyndon, 
Minnesota, 13 to 35 feet below the surface, and numerous other 
observation of remains of vegetation elsewhere along the Red 
River valley in these beds, demonstrate that lake Agassiz had 
been drained away, and that the valley was a land surface, sub- 
ject to overflow by the river at its stages of flood when these re- 
mains were deposited.* Even at the present time much of the 
area of stratified clay that almost continuously forms the central 
part of the valley plain is covered by the highest floods and prob- 
ably no portion of it is more than ten feet above the high water 
line of the Red River and its tributaries. The position of the 
thick beds of fine silt and clay in the central depression of the 
Red River valley shows that they were not mainly deposited by 
the waters of lake Agassiz, which must have spread them some- 
what equally over both the lower and higher parts of the lacus- 
trine area ; but instead appears to prove that at least their upper 
and greater part was brought by the rivers which flowed into this 
hollow and along it northward after the glacial lake was with- 
drawn. 
BIBLIOGRAPHY OF NORTH AMERICAN VERTE- 
BRATE PALEONTOLOGY FOR THE 
YEAR 1890. 
By John Eyerman, Easton, Pa. 
1. BAUR, G- Kadal. iosaurus priscus Credner. A New Reptile 
from the Lower Permian of Saxony. Am. J. Sci. 39, 
Feb., 1890. pp. 155-56. 
2. BAUR, G. On the Classification of the Testudinata. Am. 
Nat. 24, June, 1890, pp. 530-36. 
3R*. BAUR, G. Prof. Marsh on Hallopus and other Dinosaurs. 
Am. Nat. 24, June, 1890, p. 569. 
A criticism of Prof. Marsh's paper, which appeared in 
Am. J. Sci. 39, May, 1890. 
4- CANNON, Jr., G. L. "Informal Communications." 
Proc. Colo. Sci. Soc. 3, 1889, part 2, pp. 190 and 215. 
Very brief notes on dinosaurs from near Denver, Colo. 
*Geology of Minnesota, vol. ii, pp. 529, 530, 663-4 and 668-9 
