THE 



AMERICAN JOURNAL OF SCIENCE 



[THIRD SERIES.] 



Art. XXIY. — Further Studies of the Drainage Features of 

 the Upper Ohio Basin ; by T. C. Chamberlin and Frank 

 Leverett.* 



Introduction. 



In the year 1885 the senior writer, in association with Mr. 

 Gr. K." Gilbert, made a study of the drainage and drift phe- 

 nomena of the upper Ohio basin. In 1886 work was resumed 

 but was interrupted by other duties. In 1890 the junior 

 writer, working under the direction of the senior writer, gath- 

 ered data relative to the drainage history of the region while 

 tracing the group of terminal moraines across northwestern 

 Pennsylvania. During the present year he has undertaken a 

 more systematic study of the subject. 



We have found the work of Mr. J. F. Carll, of the Pennsyl- 

 vania Geol. Survey, on the old drainage systems of the region 

 especially valuable and admirable.f We are also indebted to 

 the contributions of Messrs. Chance,;}: White,§ Stevenson, | 



* Presented in abstract to the Geological Society of America, Dec. 31st, 1893. 



f Penn. Second Geol. Survey, Rept. Ill, 1880, pp. 1-10, 330-439; Rept. IIII, 

 1883, pp. 1-147, 169-175. 219-406. 



JPenn. Second Geol. Survey, Rept. YY, 1880, pp. 17-20. 



§Penn. Second Geol. Survey, Rept. Q, 1878, pp. 9-17, QQ, 1879, pp. 10-20. 

 This Journal, III, vol. xxxiv, 1887, pp. 374-381. Bull. Geol. Soc. Amer., 

 vol. i, 1880, pp. 477-479. Also discussions of drift and drainage features 

 incorporated in the detailed geology of the several counties covered by reports 

 Qt QQ-. QQQ QQQQ, namely, Beaver, North Allegheny, South Butler, Lawrence, 

 Mercer, Crawford and Erie. 



| Penn. Second Geol. Survey, Rept. K, 1876. pp. 11-19, KKK, 1878, pp. 251- 

 263. This Journal, III, vol. xv, 1878, pp. 245-250. Proc. Amer. Phil. Soc, 

 vol. xviii, 1880, pp. 289-316. 



Am. Jour. Sol— Third Series, Vol. XLVII, No. 280.— April, 1894. 

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