Personal and Svientitic JS^ews. 401 
Leverett. and he ably sets forth the evidence of siiceespive 
stages or epochs of the Ghicial period. The average thickness 
of the drift in northern Indiana is estimated to be 250 feet, or 
perhaps even more than 300 feet. w. u. 
Geology ix the Colleges and Univkksities of the United 
States. 
Under tills title. Mr. T. C. Hopkins contributes a valuable 
statistical paper of 54 ptiges in the report of the Commissioner 
of Education for the year 1893-94, Avhich was publislied and 
distributed a few months ago. Definite statements are given 
concerning the time devoted to geological instruction, the sev- 
eral courses offered to students, opportunities for field work, 
and the laboratory, museum and library equipment, in each of 
the 378 collegiate institutions of the'United States which give 
instruction in this science. In twenty-four colleges, geok)gy 
is taught by the president; and in seven colleges by a lad}^ 
professor or instructor. During the year of this report, sixty- 
eight graduate students were making a specialty of geology, 
including eighteen in Johns Hopkins University, thirteen in 
the University of Chicago, and eleven in Harvard Universit}^ 
AV. r. 
Geologic Atlas of the United States. 
Seven new folios of this admirable atlas, with descriptive 
text, have been recently issued, as follows: 
21. Pikeville folio, in Tennessee, by Charles Willard Hayes. 
22. McMinnville folio, in Tennessee, also by Mr. Hayes. 
23. Nomini folio, in Maryland and Virginia, by N. H. Dar- 
ton. 
24. Three Forks folio, in Montana, by A. C. Peale. 
25. Loudon folio, in Tennessee, by Arthur Keith. 
26. Pocahontas folio, in Virginia and West Virginia, by 
Marius R. Campbell. 
27. Morristown folio, in Tennessee, bj' Arthur Keith. 
Each folio maps an area bounded by arcs of a half degree, 
excepting that of Three Forks, which measures one degree on 
each side. The scope of the maps and descriptions, including 
ample details of the topograph}-, local formations, and mate- 
rial resources, was stated in the American Geologist for last 
March (vol. xvii, pp. 177-179), with notes of the previous 
twenty folios. w. u. 
According to Mk. S. F. Emmons there are in the Black 
Hills three types of gold deposits: The Homestake type of 
deposit, the siliceous gold ores of the Cambrian, and the pla- 
cer deposits. The first occur in sheets often several hundred 
feet wide along a mineral-bearing zone, which is mostly con- 
trolled by the Homestake company, and is now worked to a 
vertical depth of 800 feet. The placer deposits are ])artly 
ancient or fossil placers at the base of the Cambrian (Middle 
