DEVONIAN 285 



some pyroclastics and are similar to those of the upper Yukon, with 

 which they may be provisionally correlated. 



The Devonian of the Kampart region has been recently described by 

 Prindle/" and he has recognized two subdivisions under this heading: 

 (1) A lower, which may be Silurian, made up chiefly of cherts, argillites, 

 and greenstones, and (2) an upper or true Devonian, consisting of 

 massive limestones, greenstones, red, green, and black argillites, quartz- 

 ites, and conglomerates. The limestones carry fossils, assigned to the 

 Middle Devonian. Of these terrains it is probal^ly safe to say that they 

 represent in a general way the igneous group of the upper Yukon, though 

 close correlations can not now be made. 



Devonian limestone has been found in the Mount McKinley region and 

 in the middle Kuskokwim*^ valley. Keele has described some limestones," 

 quartzites, and slates which outcrop in extensive areas in the upper part 

 of the Stewart Eiver^- basin and assigned them to the Devonian. The 

 evidence that this series is Devonian would appear to be far from con- 

 clusive, but it can hardly be questioned that they are Paleozoic. In a 

 personal letter Mr Keele presents a measured section of these rocks which 

 shows a greenish quartzite (450 feet) at the bottom, succeeded by over 

 3,000 feet of argillites, with some arenaceous and calcareous rocks, and 

 then overlaid by some 600 feet of sandstones, grits, and fine conglomer- 

 ates. Tlie whole section measures about 4,200 feet. Their succession 

 does not bear much resemblance to any of the rocks of the Upper Alaska- 

 Yukon section, but it is not unlike some of the terrains of the Eampart 

 district which have been provisionally assigned to the Devonian. 



In the region north of the Yukon Devonian terrains have not been defi- 

 nitely recognized, but fossils found in the alluvium point to the presence 

 of Devonian rocks in the area drained by the Chandlar river.^^ 



The Devonian fauna which has been described from the Mackenzie 

 Eiver district by j\Ieek^* and Whiteaves^^ represents apparently about the 

 same general horizon as the lowest Devonian limestone fauna on the Por- 

 cupine and Yukon, but there are comparatively few species comnaon to 

 tlie two. No Lower Devonian fauna has been reported from the Mac- 



^ L. M. Prindle : The Fairbanks and Rampart quadrangles. Bulletin no. 327, U. S. 

 Geological Survey. 



^ J. E. Spurr : A reconnaissance in southwestern Alaska. Twentieth Annual Report, 

 U. S. Geological Survey, part vii, pp. 157-159. 



^- J. Keele : Report on the Upper Stewart River region, Yukon. Geological Survey of 

 Canada, no. 94.3. 1906, Ottawa, p. 14C. 



*^ F. C. Schrader : A reconnaissance along the Chandlar and KoyuUuk rivers. Twenty- 

 first Annual Report, U. S. Geological Survey, part ii. p. 476. 



"Transactions of the Chicago Academy of Science, vol. 1, 1969, pp. 01-114. pis. 11-15. 



*^ Geological Survey of Canada, Contributions to Paleontology, vol. 1, part 3, 1891, pp. 

 197-253, pis. 27-32. 



