F. B. Taylor. Origin of the Gorge of the Whirlpool Rapids at Niagara, Bull. Geol. Soc. Am., vol. 9, 1898, pp. 59-84.
A. W. Grabau. Guide to the Geology and Paleontology of Niagara Falls and Vicinity, Bull. N. Y. State Mus., vol. 9, No. 45, 1901, pp. 1-85, pls. 1-11.
J. W. Spencer. The Falls of Niagara, etc. Dept. of Mines, Geol. Surv. Branch, Canada, 1907, pp. 490, pls. 43.
G. K. Gilbert. Rate of Recession of Niagara Falls, etc. Bull. 306, U. S. Geol. Surv., 1907, pp. 31, pls. 11.
G. de Geer. Quaternary Sea Bottoms of Western Sweden. Paper 23, Livret Guide Cong. Géol. Intern., 1910, pp. 57, pls. 3.
CHAPTER XXVI
LAND SCULPTURE BY MOUNTAIN GLACIERS
Contrasted sculpturing of continental and mountain glaciers.—In discussing in a previous chapter the rock pavement lately uncovered by the Greenland glacier, we learned that this surface had been lowered by the processes of plucking and abrasion, the combined effect of which is always to reduce the irregularities of the surface, soften its outlines, and from sharply projecting masses to develop rounded shoulders of rock—roches moutonnées.