43^ . NEW YORK STATE MUSEUM 



unquestionably formed by some operation different from, and ante- 

 cedent to, that which produced the water-arranged gravels and 

 eskers. Deposits of water-formed gravel, etc., clearly of later date, 

 often occur in the lower ground between the drumlins, and even 

 banked up against them." 



The authors apparently regarded their drumlins as constructional 

 forms and did not regard the matter as needing discussion, since 

 they refer to the origin of the drumlins only incidentally, as follows: 



'* No agent which can not do both kinds of work, rock-scoring and 

 drumlin-heaping, can be proposed as having caused them " [p. 9]. 



". . . And it has formed the drumlins by an operation evidently 

 similar to that by which a stream of water often makes longitudinal 

 ridges of sand in its bed." 



Bibliography 



The following list of writings in English relating to drumlins is 

 not exhaustive, and it is possible that some valuable references have 

 been overlooked, specially of foreign authors. Numerous incidental 

 references have been purposely omitted. Outside of English the 

 literature seems scanty, but an important paper in German is noted 

 on page 394. 



Persons unfamiliar with the phenomena of drumlins might well 

 begin the study by reading the paper by W M„ Davis that is given 

 as his fourth title in the following list; and later the papers by 

 Warren Upham for the years 1889, 1892 and 1893. 



Barton, G. H. Bost. Soc. Nat. Hist. Proc. 1892. 26: 23-25. 



Glacial Origin of Channels on Drumlins. Geol. Soc. Am. Bui. 1894. 



6:8-13. 

 Bonney, T. G. Ice-work, Past and Present. 1896. p. 116-19. 

 Chalmers, Robert. Geol. & Nat. Sur. Can. xVn. Rep't. n. s. i888-8g. 



p. 23 N. 

 Chamberlin, T. C. U. S. Geol. Sur. 3d An. Rep't. 1881-82. p. 306. 



Geol. Wis. 1883. 1: 283. 



Am. Ass'n Adv. Sci. Proc. 1886. 35: 204. 



Horizon of Drumlin, Osar and Kame Formation. Jour. Geol. 1893. 



1: 255- 6 7, 521-24. 



Am. Geol. 1893. 12: 176. 



Geol. Soc. Am. Bui. 1895. 6: 216. 



The Great Ice Age. Ed. 3. 1895. p. 743-45. (James Geikie) 



& Salisbury, R. D. Geology. 1906. 3: 360. 



