74 



HOBBS— CHARACTERISTICS OF THE 



[April 22, 



of volume incidental to extreme temperature range (see Fig. 13). 

 This explanation in temperature changes would leave the absence 

 of such structures in other places wholly unaccounted for, and we 

 venture to believe that a recent trough faulting within the rock 

 basement below the ice and communicated upward through it, 

 would furnish a more reasonable assumption, particularly in view of 

 our later knowledge of dislocations connected with earthquake dis- 

 turbances. 



Fig. 13. Hypothetical cross section of a glacial canal upon the inland- 

 ice of North East Land (after Nordenskiold). 



Fig. 14. Map showing the supposed area of inland-ice upon Grinnell 

 and Ellesmere Lands (from Andree's " Handatlas "). 



Still deeper in-breaks of the ice were encountered within the 

 same region. These, though deeper, were generally of less extent, 

 and were designated by the sailors of the party " docks " or " glacier 

 docks." 



The Inland-ice of Grinnell, Ellesmere and Baffin Lands. — 

 Something has been learned of the inland-ice of Grinnell Land (see 

 Fig. 14) from the report of Lieutenant Lockwood upon his cross- 

 ing of Grinnell Land in 1883.^^ Of especial interest is his descrip- 

 tion of the ice front or face as it was observed for long distances 



" A. W. Greely, " Report on the Proceedings of the United States 

 Expedition to Lady Franklin Bay, Grinnell Land," Vol. i, especially Appendix 

 No. 86, pp. 274-279, pis. 1-4. See also Salisbury, Jour. GeoL, Vol. 3, p. 890. 



