REVIEW OF GEOLOGIC INVESTIGATIONS 257 



Eobert Kennicott 'and William H. Dall were the pioneer scientists in 

 this field. In 1861 Kennicott, follo-vving the old Hudson Bay route from 

 the Mackenzie river, crossed the divide at the head of the Porcupine and 

 wintered at Fort Yukon,^ at its mouth. Six years later Doctor Dall, as a 

 member of the Western Union Telegraph expedition, reached the same 

 point by an up-river journey from- the mouth of the Yidvon.* 



In 1888 McConnell,^ of the Geological Survey of Canada, made an ex- 

 ploratory trip from the Mackenzie across to the Porcupine and down that 

 river to the Yukon, then up the Yukon to its junction with the Pelly and 

 Lewes. He was the first to obtain a clue to the bedrock geology of the 

 particular field here to be discussed. The same year Ogilvie," Dominion 

 land surveyor, explored the headwaters of the Porcupine and collected 

 some geologic data. 



Two years later EusselF carried a geologic reconnaissance from the 

 mouth of the Yukon to its headwaters, returning to the coast by way of 

 the Chilkoot pass. Eussell's hasty trip yielded some few notes on the bed- 

 rock, but his observations were largely devoted to the problems connected 

 with the surface features. 



In 1896 Spurr^ made the first systematic surveys of any portion of the 

 Alaska- Yukon. His report still remains the standard work of reference 

 on this field, and much of the stratigraphic nomenclatu.re which he intro- 

 duced has found a permanent ^jlace in the literature. 



Brooks^ traversed the eastern end of this field in 1898, and in the 

 following year^* extended his observations in the same general area. The 

 region lying north of the Yukon was first explored by Schrader^^ in 1899, 

 who two years later extended his'- investigations northward to the Arctic 



» William H. DaU : Alaska and its resources. Boston, 1870, p. 349. 



* Ibid., pp. 74-115. 



^ R. G. McConnell : Report on an exploration in the Yukon and Mackenzie basins, 

 Northwest Territory. Annual Report of the Geological and Natural History Survey of 

 Canada, new series, vol. 74, 1890, pp. 5-144D. 



* William Ogilvie : Exploratory survey of part of the Lewes, Tatonduc, Porcupine, 

 Trout, Peel, and Mackenzie rivers. Interior Department of Ottawa, 1890. 



' I. C. Russell : Notes on surface geology of Alaska. Bulletin of the Geological Soci- 

 ety of America, vol. 1, 1890, pp. 72-99 and 154-15.5. 



* J. E. Spurr : Geology of the Yukon gold district, Alaska. Eighteenth Annual Report, 

 V. S. Geological Survey, part 3, pp. 87-392. 



* Alfred H. Brooks : A reconnaissance on the White and Tanana basins. Twentieth 

 Annual Report, U. S. Geological Survey, 1900, pp. 425-494. 



"• Alfred H. Brooks : A reconnaissance from Pyramid harbor to Eagle City. Twenty- 

 first Annual Report, U. S. Geological Survey, part ii, pp. 331-391. 



"■ F. C. Schrader : Preliminary report on a reconnaissance along Chandlar and Koyu- 

 kuk rivers, Alaska, in 1899. Twenty-first Annual Report, U. S. Geological Survey, part 

 11, 1900, pp. 441-486. 



" F. C. Schrader : A reconnaissance in northern Alaska. Professional paper no, 20, 

 D. S. Geological Survey, 1904. 



