Correspondence. 257 
Springer, Frank. 
Further note on Uintacrinus. (Am. Geol., vol. 26, p. 194. Sept. 
1900.) 
Williams, I. A. 
Geology of Worth county. (Geol. Sur. Iowa, vol. 10, pp. 3\7-Z77- 
Ann. Rep. 1899.) 
Winchell, A. N. 
Mineralogical and petrographic study of the gabbroid rocks of 
Minnesota, and more particularly of the plagioclasytes (I), (Am, 
Geol., vol. 26, pp. 151-18S, plates 8-19, Sept. 1900.) 
CORRESPONDENCE. 
Remains of the Mammoth in Arizona. The upper jaw and 
teeth of a mammoth, presumably Elephas americanus, were recently ex- 
humed from the ancient alluvions of the Colorado river at Yuma, Ari- 
zona. One of the lower molars together with fragments of the tusks 
were also found. The alveoli of the tusks are about seven inches in di- 
ameter. Other bone's were broken up and lost before the relics were 
lirought to the notice of Mr. Herbert Brown, who sent them to the 
museum of the University of Arizona at Tucson. 
This discovery is interesting, showing the former presence of the 
mammoth in Arizona; extending knowledge of its range on the Pacific 
slope and in connection with the discovery of remains of the mastodon* 
and of the giant bos or bison,t indicating former conditions of greater 
precipitation, moisture and vegetation in that region, now noted for its 
aridity. Wm. P. Bi.AKE. 
University of Arizona, Tucson, June, igoo. 
Dr. Angelo Heilprin and the Decrease of Water in Lake 
Nicaragua.. — Dr. Angelo Heilprin has published two or three papers 
recently — the most recent in the "Supplement to the Scientific Ameri- 
can" — in which he declares that the supply of water in lake Nicaragua 
■"is from some unaccountable cause rapidly decreasing." Between 1880 
and 1890 he declares that the decrease has been more than 20 feet, and 
refers, as data for his statement, to reports of engineers made, some a 
century ago, to the reports by Mr. A. P, Davis, hydrographic engineer 
to the Interoceanic Canal Commission. 
The facts in the case are: There never was a reliable instrumental 
survey made and revised for corrections or confirmations until that made 
5n 1898-99 by Mr. A. P. Davis or his corps of hydrographic engineers. 
In this report they do not declare that there is any decline in the wa- 
ter level in lake Nicaragua between 1880 and 1898, nor earlier nor 
later. 
♦American Geologist. 
■fAMERICAN GeOLOCJI.ST. 
