WORKS AND MEMOIRS ON MOUNTAIN-MAKING, ETC. 835 



J. D. Whitney: Earthquakes, Volcanoes, and Mountain Building, North American 

 Review, 1871, and also as a separate volume, 1871. 



N. S. Shaler: On the Formation of Mountain Chains, Proc. Soc. Nat. Hist., Bos- 

 ton, June, 1866, and Geol. Mag., v. 511. 



Joseph Le Conte : Formation of the Great Features of the Earth's Surface, Amer. 

 J. Sci., III., iv., 460, 1872, v., 156, 448 (the last in reply to T. S. Hunt) 1873. —Struc- 

 ture and Origin of Mountains, ibid., xvi., 95, 1878; Elements of Geology, 8vo, 1878; 

 advocates the making of mountains by lateral pressure as a result of the earth's con- 

 traction, and the existence of a semi-fused (aqueo-igneously) layer between the earth's 

 crust and a solid nucleus. 



Dutton : Critical Observations on Theories of the Earth's Physical Evolution, Amer. 

 J. Sci., II., viii., 113, 1874; Penn. Monthly, 1876. 



F. V. Hayden : Reports of the Geological Survey of the Territories, 1867-1876. 



J. W. Powell,: Exploration of the Colorado River and its Tributaries, Washington, 

 1875. — Geology of the Eastern Portion of the Uinta Mountains and a region of Coun- 

 try adjacent thereto, with a Polio Atlas, 4to, Washington, 1876. — Geological Structure 

 of Country North of Grand Cafion of Colorado, Amer. J. Sci., III., v. 456, 1873; de- 

 scribes the great monoclinal uplifts and faults. — Types of Orographic Structure, ibid., 

 xii., 414, 1876. 



G. K. Gilbert : Report on the Geology of portions of Nevada, Utah, California, 

 and Arizona, in 1871, 1872, 1873, Wheeler Expedition, 4to, iii., Geology, 1875; con- 

 tains, besides an account of the geology of the region, and a discussion of the subjects 

 of mountain structure and erosion, a long list of the hot springs of the United States. 

 — The Colorado Plateau, Amer. J. Sci., III., xii., 16, 85, 1876. — Report on the Henry 

 Mountains, 4to, 1877; Amer. J. Sci , xix., 1880. 



Clarence King: Systematic Geology (1879), being vol. i. of the Reports (4to) on 

 the Survey of the 40th Parallel ; attributes the fusion of subterranean regions, and con- 

 sequent volcanic action over a part of western North America, to the diminution of 

 pressure resulting from the removal of surface rocks by erosion. 



3. List of Papers on the Taconic System. 



I. In favor of its inferior position and uncomformability to the Neio York Silurian. 



Ebenezer Emmons: Rep. Geol. New York, 4to, 1842, pp. 113-164; announces the 

 Taconic system as Lower Cambrian, and includes in it, besides the schists of the Ta- 

 conic Mountains (in the vicinity of which, at Williamstown, Professor Emmons for a 

 while lived), also the associated crystalline and semicrysralline limestones and quartz- 

 yte. — Idem : Rep. Agric. New York, Part v., 4to, 1846, pp. 45-112; describes the sys- 

 tem with more detail, and extends it to include rocks in Maine, Rhode Island, and 

 Michigan. — Idem: American Geologist, 8vo, vol. i., 1855, Part ii., pp. 1-124; ex- 

 tends the system from Maine to Georgia, divides it into Upper and Lower, the slates, 

 limestones, and magnesian slates of the original Taconic (with their supposed equiva- 

 lents) being made the Lower, and some added fossiliferous rocks [Primordial and later] 

 the Tapper. — Idem: Report on the North Carolina Geol. Survey, 8vo, 1856, pp. 49-72. 



F. Marcou, Comptes Rendus, Nov. 4, 1861, and Proc. Boston Soc. Nat. Hist., 1862 ; 

 adds the Potsdam sandstone and the gneiss of the Green Mountains to the Taconic 

 system. 



T. S. Hunt: Proc. Boston Soc. Nat. Hist., xix., 275, 1878; refers the "Upper 

 Taconic," "wholly uncrystalline," to the Quebec Group, but the "Lower Taconic, ' ; 

 here called Taconian (and made to include the crystalline schist of the Taconic Moun- 

 tains, " along the outcrop " of which occur " the great masses of brown hematite ore *' 

 [or limonite], associated with magnesian limestones, from Vermont to Alabama), to the 

 lowest Cambrian, or a still lower formation, containing Scolithus and Eozoon. — Idem: 

 Pennsylvania Geol. Report, on Azoic Rocks, Part i., 1878 ; uses the name Taconian, 

 with the same definition, "but makes the Upper Taconic to include organic remains of 

 the European Cambrian, at least as low as the Menevian." 



II. In favor of the identity of the Taconic system with part or all of the New York 

 Lower Silurian. (The Lower Silurian is called the Champlain Division by Mather.) 



