62 The Amevican Geologist. July, 1895 
The intercalated till is mjiny feet above any other known j;iacial drift 
in the vicinity. It is referred to deposition from a mass of floating ice 
laden with debris from the adjacent ice-sheet. The origin of the drift 
generally in the surrounding region to the south of the Altamont or 
outermost moraine, which lies at a distance of 20 to 30 miles north of 
Sioux City, is supposed by the authors to have been likewise from float- 
ing bergs and floes. The extramorainic till there "is thin and patchy, 
being usually not over fifteen feet in thickness. That the region has 
not been covei'ed by the heavy land ice would seem to be indicated, not 
onl.y by this, but also by the general presence of beds of fine sand and 
clay under the drift, and showing no signs of disturbance." w. u. 
Pregldcial Elevation of Iowa. By Jiy H. Fostkk Hain. (Proc. Iowa 
Acad, of Sciences, vol. ii, pp. 23-26.) Numerous deep, drift-filled val- 
leys, cut 100 to 300 feet below the general surface of the bed-rocks, are 
described as found by well borings throughout Iowa, and their erosion 
is good evidence of a long preglacial period of considerable elevation. 
It remains undetermined, however, whether this valley erosion took 
place chiefly during the great Tertiary cycle of base leveling, or during 
the less prolonged early Pleistocene period of renewed uplifting and 
stream channeling which immediately preceded the Ice age. w. u. 
A Bibliography of North American Paleontolo(jy, 1SSS-1S92. By Chari.es 
ROLLIN Keyes. (U. S. Geological Survey, Bull. No. 121, 251 pp., 1894.) 
This work embraces: (1) An author's list, in which is given the full 
title, volume, etc. Each title is -followed by a- brief synopsis of the 
paper, an enumeration of the new genera and species described, and a 
list of forms already known, which are described and figured anew. 
(2) A title index. (3) Subject entries and cross references. Under 
the last head each article is included under its appropriate biological, 
geological and geographical divisions. 
The present bibliography is tlnis seen to be much more complete than 
most works of a similar nature. In addition to being an index and 
catalogue, it is really a condensed review of all literature pertaining to 
paleontolog}- published during the period from 1888 to 1892. It is thus 
of great aid to those who do not have access to a complete library. The 
amount of work required to produce such a bibliography as the above 
must have been very considerable, but its usefulness to the paleontolo- 
gist and to the general geologist will fully compensate for the labor be- 
stowed u[)on it. u. s. G. 
RECENT PUBLICATIONS. 
/. Government and State liepoj'ts. 
Geol. Survey of Ga., Bull. 2. A preliminary report on the corundum 
deposits of Georgia, F. P. King. 133 pj)., (i i)is., 1 map, 1894. 
N. Y. State Mu.seum, 47th Ann. Kei)t. for 1893; 1137 pp., numerous 
plates and sections, 1894. Official reports; The Livonia salt shaft, its 
