PALEONTOLOGY: H. F. OSBORN 
265 
The status of the mixture is described in the table. 
Professor Harry F. Reid informs me that a continental sheK of the Atlantic 
Ocean has a very definite slope which is very nearly that obtained for the 
extremely wet sand in these experiments. 
I reserve the mathematical theory for a future paper. 
SAND 
WATER 
ANGLE OF 
REPOSE 
REMARKS 
pounds 
pounds 
10 
0 
33° 
Dry 
10 
0.5 
65° 
Not hard 
10 
1.0 
120° 
Not accurate, but large obtuse angle, hard 
10 
1.5 
120°-140° 
Not accurate, but large obtuse angle, hard 
10 
2.0 
120°-140° 
Not accurate, but large obtuse angle, hard 
10 
2.5 
120° 
Not accurate, but large obtuse angle, hard 
10 
3.0 
48° 
Fairly hard 
10 
3.5 
19° 
All mixes 
10 
3.75 
14.5° 
Very slight excess of water 
10 
4.0 
13° 
Water not all absorbed 
10 
5.0 
12° 
Excess of water 
The sand has been meshed by Professor Roys of the Worcester Polytechnic 
Institute with the following results: 
SIZE OF SCREEN 
DIAMETER OF OPENING 
PER CENT OF SAND WHICH PASSED 
THROUGH 
meshes 
inches 
200 
0.0029 
7.3 
100 
0.0055 
29.55 
50 
0.011 
84.60 
30 
0.022 
99.45 
20 
0.034 
99.85 
10 
0.073 
99.95 
4 
0.20 
100.00 
PAL^OMASTODON, THE ANCESTOR OF THE LONG- J AWED 
MASTODONS ONLY 
By Henry Fairfield Osborn 
American Museum op Natural History, New York City 
Read before the Academy, April 29, 1919 
In 1900^ the author predicted that the ancestors of the Proboscideans, 
as well as of the Hyracoidea and some other orders of mammals, would be 
discovered in Africa. Two years later the members of the British Geological 
Survey of Egypt discovered in the Ohgocene of the Fayum remains of PalcBo- 
