Alkali Deposits of H'yoming. — Read 169 
were deposited, Ijut in such case it is difficult to see why 
sodium chloride is entirely absent in nearly every instance. 
The most definite statement that it would seem safe to offer 
is that they must have been produced during rock decomposi- 
tion by chemical reactions, the exact cause of which is not 
known. Se& the work of Hilgard on alkali in soils. 
SUMMARY. 
1. Deposits of sodium and magnesium sulphates of great 
extent exist in south central Wyoming. 
2. These deposits offer a valuable source of sodium and 
its salts. 
3. The salts ap]:)ear to have been in part brought to the 
surface by uprising waters and in part derived from the leach- 
ing of the surrounding strata. 
4. The origin of the salts has not yet been satisfactorily 
explained. 
April, 1904, Departnient of Geology, University of IVyonp- 
iii r. 
NOTES ON THE PLEISTOCENE FAUNA OF 
SANKATY HEAD, NANTUCKET, MASS. 
By Joseph A. Cushman, Boston. Mass. 
The geological events of this interesting locality have been 
a matter of considerable discussion since they were first defi- 
nitely treated by Desor and Cabot in 1847. The section ex- 
posed has changed somewhat in the ensuing time and only a 
portion of the original section is now exposed. The details 
of this are given by Merrill and are reproduced here. 
1. Fine dark drifted sand 3 ft. 
2. Yellow sandy drift 5 " 
3. Coarse gray stratified sand, etc 40 
4. ' Fine white clayey sand, etc 10 
5. Fragment Bed. [4] i 
6. Upper shell Bed [3I 8 in. 
7. Clayey ferruginous layer 4 
8. Serpula sand [2] i " 3 
9. Lower shell Bed [i] 9 
10. Red sand with clay i 
11. White sand 4 
Concealed 24 
Total go ft. 
