28 BIBLIOGRAPHY OP NOBTH AMERICAN GEOLOGY, 1906-1907. 
Blackwelder, Eliot. 
238. On the probable glacial origin of certain folded slates in southern 
Alaska.— Jour. Geology, vol. 15, no. 1, pp. 11-14, 1 fig., 1907. 
Describes the position and lithologic characters of a shale or slate conglomerate near 
Yakutat Bay and discusses its age and mode of formation. 
239. Glacial features of the Alaskan coast between Yakutat Bay and the 
Alsek River. — Jour. Geology, vol. 15, no 5, pp. 415^33, 9 figs., 1907. 
240. Reconnaissance of the Pacific coast from Yakutat to Alsek River. — 
Abstract: IT. S. Geol. Survey, Bull. no. 314, pp. 82-88, 1907. 
Describes the geologic formations and physiography. 
Blake, William P. 
Origin of orbicular and concretionary structure. Am. Inst. Min. Eng., Trans., 
vol. 36, pp. 39-44, 1 pi., 1900 (Bi-Mo. Bull., no. 4, pp. 077-0S2, 1905).— See Blake, 
19, page 39 of Bulletin no. 301, II. S. Geol. Survey. 
241. Origin of the depression known as Montezuma's Well, Arizona. — Sci- 
ence, new ser., vol. 24, p. 568, November 2, 1906. 
242. The flanking detrital slopes of the mountains of the Southwest. — Sci- 
ence, new ser., vol. 25, pp. 975-978, June 21, 1907. Abstract: Science, new ser., 
vol. 25, p. 294, February 22, 1907. 
Describes the character of these slopes in the Great Basin of Nevada and the Pied- 
mont region of Arizona and discusses their origin. 
Blatchley, Raymond S. 
243. The Princeton petroleum field of Indiana. — Indiana, Dept. Geol. and 
Nat. Res., 31st Ann. Rept., pp. 559-593, 3 figs., 1 map, 1907. 
Blatchley, W. S. 
244. The Indiana of nature: Its evolution. — Indiana Acad. Sci., Proc. 1903, 
pp. 33-59, 6 figs., 1904. 
Describes the geologic history of Indiana. 
245. The petroleum industry of southeastern Illinois. — Illinois State Geol. 
Survey, Bull. no. 2, 109 pp., 6 pis., 3 figs., 1906. 
Gives a general account of the oil and gas developments of Illinois, discusses their 
origin and mode of occurrence, and describes in detail the oil fields in the southeastern 
part of the State. E. E. Grout contributes (p. 74) data regarding Randolph County and 
T. E. Savage (pp. 77-87) concerning the Pike County gas field. 
246. The geologic distribution of the road materials of Indiana. — Indiana, 
Dept. Geol. and Nat. Res., 30th Ann. Rept., pp. 120-160, 1906. 
Describes the origin and occurrence of gravel deposits and the occurrence and geologic 
horizon of limestones suitable for road-making materials. 
247. The natural resources of Indiana. — In Dryer's Studies in Indiana 
Geography, pp. 61-71, 1907. — See no. 745. 
248. The natural resources of the State of Indiana. — Indiana, Dept. Geol. 
and Nat. Res., 31st Ann. Rept., pp. 13-72, 3 pis., 1907. 
249. The petroleum industry in Indiana in 1906. — Indiana, Dept. Geol. and 
Nat. Res., 31st Ann. Rept., pp. 429-558, 7 figs., 1 map, 1907. 
Includes a general discussion on the occurrence and origin of petroleum and condi- 
tions of accumulation. 
Blatchley, W. S., and assistants. 
250. The roads and road materials of Indiana. — Indiana, Dept. Geol. and 
Nat. Res., 30th Ann. Rept., pp. 17-1057, 25 pis., 59 figs, (outline maps), 1906. 
Includes notes on the geologic occurrence of road-making materials. 
