1891.] Proceedings of Scientific Societies. 401 
Dr. Dall stated that he had lately visited the Peace Creek locality 
for the special purpose of settling the age of the deposit. He explained 
the method of dredging for the phosphate in the river, stating that 
200 tons per day were obtained. It is mostly in the form of pebbles 
about the size of marbles. Above Arcadia he found a section along 
the river bank which showed a bed with the bones ¿n situ. The layer 
was about 11% feet thick, overlying strata of Pliocene age (as shown 
by marine shells) ; and the bone bed was in turn overlain by a deposit 
of phosphatic material. The bones, therefore, could not be older 
than the Pliocene, and as the marl above them was covered in turn by 
astratum which also contains Pliocene marine fossils, the conclusion 
was inevitable that the bone beds of that locality, at least, were of 
Middle Pliocene age. 
Dr. R. W. Shufeldt read a paper ‘‘ On a Collection of Fossil Birds 
from the Equus Beds of Oregon,” from the collection of Prof. E. D. 
Cope. He first described the features of Silver Lake, a beautiful sheet 
of water frequented by great numbers of water birds. ‘‘ Fossil Lake” 
was the bed of a dried-up lake, not many miles distant; and in the 
fine silt of this locality many bird remains had been discovered by 
Prof. Condon and Prof. Cope. He thought there were at least twenty 
undescribed extinct species. Indian relics, implements of obsidian, 
were found in the same bed as the bird remains, though it could not 
be asserted positively that the two were contemporaneous. 
Mr. F. A. Lucas spoke of the anatomy of Hesperornis, the gigantic, 
extinct, toothed bird. He compared it with various living birds, and 
concluded the evidence indicated a foot patterned after that of the 
grebe, but more highly specialized. With Marsh he did not think it. 
was a land bird, or that it used its wings in swimming, but that it was 
a highly specialized aquatic. 
r, F. H. Knowlton discussed the function of cypress knees. He 
referred to the idea advanced in 1848 that these knees, which vary in 
height from one inch to two, four, and even ten feet, performed the 
function of aération. This idea had been later on fully elaborated by 
Prof. N. S. Shaler. Another theory, advanced by Dr. Lamborn, is 
that the knees buttress the trees, and so prevent violent winds from 
uprooting them. The latter idea seemed very plausible, as it was an 
undoubted fact that no one had ever seen an uprooted cypress tree. 
Prof. Shaler had contended that when the knees were submerged the 
tree invariably died, but this was stated not to be the case. 
of. L. F. Ward, in discussing the paper, expressed his disbelief in 
the theory that the knees were for the purpose of increasing the areat- 
