PALEOZOIC UNDIVIDED. 353 



preserved, but which seem to be crinoid stems. In an exposure of limestone near the top of 

 Buckhorn Mountain, in the northwest part of Republic quadrangle, several fossil crinoid stems 

 were found which are not out of harmony with a provisional assignment to the Carboniferous. 

 These remains, together with the lithologic characteristics of the series, suggest a correlation 

 with the Cache Creek series of Dawson," which is of Carboniferous age. On lithologic grounds, 

 however, it is thought that rocks of more than one age are present. 



N 10-11 TO Q 7-9. BRITISH COLTIMBIA AND YUKON. 



The large area mapped as Paleozoic in British Columbia and Yukon is so 

 assigned on the work of the Canadian Geological Survey and chiefly on that of Dr. 

 George M. Dawson. The Cache Creek group is largely represented and is described 

 in Chapter VIII (p. 390) . But there are in the region also other terranes which can 

 not be separated, as the country is largely unknown and the geologic relations are 

 intricate. 



O-B 2-8. ALASKA. 



It is probable that the rocks in Alaska mapped as metamorphic Paleozoic 

 include strata ranging from pre-Cambrian through the Paleozoic column and may 

 possibly include some highly metamorphosed Mesozoic terranes. Adequate differ- 

 entiation is in part due to limitations imposed by the scale of the map and in part 

 to the absence of detailed field data. According to Brooks *^^ ' — 



Four belts of these younger metamorphic rocks are indicated on the map. The first 

 stretches through southeastern Alaska and probably forms the bedrock throughout the greater 

 part of the unexplored St. Elias Range. It has been identified along the lower Copper River 

 valley and in the Chugach Mountains, and then, bending to the southwest, forms the backbone 

 of the Kenai Peninsula of southeastern Alaska. Silurian, * Devonian, Carboniferous, and 

 Lower Cretaceous " fossils have been found in these metamorphic rocks of southeastern 

 Alaska. <* The metamorphic rocks of what appears to be the western end of the same belt 

 have thus far yielded no fossils, and they have been variously assigned to the Paleozoic and 

 the Mesozoic The intensely folded rocks of the Chugach Mountains may include some 

 pre-Cambrian sediments, but of this no evidence has yet been found. 



A second belt of metamorphic rocks forms the major part of the Alaska Range, and Ordo- 

 vician / fossils have been found at a horizon which probably occurs near the base of this series 

 but it is not impossible that pre-Cambrian sediments are also included. 



" Ann. Bept. Geol. Survey Canada, new ser., vol. 7, 1894, pp. 37b-49b. 



* Brooks, A. H., Preliminary report on the Ketchikan mining district, Alaska: Prof. Paper U. S. Geol. Survey 

 No. 1, 1902, pp. 16-31. 



« Wright, C. W., Beconnaissance of Admiralty Island: Bull. U. S. Geol. Survey No. 287, 1906, p. 144. 



^ In 1909 Mesozoic fossils of Jurassic or Cretaceous age were found at Berners Bay by Knopf and identified by 

 Knowlton. 



^ Bussell, I. C, Expedition to Mount St. Elias: Nat. Geog. Mag., vol. 3, 1890, pp. 173-174. Schrader, F. C. A 

 reconnaissance of a part of Prince William Sound and the Copper Eiver district in 1898: Twentieth Ann. Bept. U. S. 

 Geol. Survey, pt. 7, 1900, pp. 408^10. Schrader, F. C, and Spencer, A. C, The geology and mineral resources of a 

 portion of the Copper Biver district, a special publication of the U. S. Geol. Survey, 1901, pp. 34-37. Mendenhall 

 W. C, A reconnaissance from Besurrection Bay to Tanana Biver: Twentieth Ann. Bept. U. S. Geol. Survey, pt. 7 

 1900, pp. 265-340. Emerson, B. K., Harriman Alaska Expedition, vol. 4, New York, 1902, pp. 11-54. Martin G. C. 

 The petroleum fields of the Pacific coast of Alaska : Bull. TJ. S. Geol. Survey No. 250, 1905, p. 64. Mendenhall W. C. 

 The geology of the central Copper Biver region: Prof. Paper U. S. Geol. Survey No. 41, 1905, p. 133. Paige, S., and 

 Knopf, A., Geologic reconnaissance in Matanuska and Talkeetna basins, Alaska, Bull. U. S. Geol. Survey No. 327 

 1907. 



f Brooks, A. H., The Mount McKinley region, Alaska: Prof. Paper U. S. Geol. Siurvey No. 70, 1911, pp. 72-73. 

 48011°— 12 23 



