E. If. Kindle — Section at Cape Thompson, Alaska. 521 



obtained by them were found to be Silurian by Fisher and 

 Kupreanoff. At a much later date a brief note on a slab of 

 fossils from Cape Thompson appeared in a report by Prof. A. 

 Hyatt. These were considered to be " probably Triassic "* by 

 Prof. Hyatt. In 1896 Mr. Chas. Schuchert included in his 

 " Report on Paleozoic fossils from Alaska "f a single species — 

 Spirifer condor, which was found on the beach near Cape 

 Thompson by Mr. W. J. Fisher. A. J. Collier published in 

 1906 a sketch of the section at Cape Thompson as seen from 

 a steamer in passing the Cape. J 



Although mentioned, as noted above, by various subsequent 

 writers, little has been added to the information furnished by 

 Mr. A. Collie's notes published more than three-quarters of a 

 century ago. 



The unaltered condition of the rocks here affords excep- 

 tional opportunities to secure perfectly preserved fossils in 

 abundance from the Carboniferous limestone, thus eliminating 

 the uncertainty which frequently attaches to the determination of 

 fossils as they are so often found in the highly altered rocks of 

 many parts of Alaska. 



General Geologic Relations. 



The oldest rocks exposed in the vicinity of Cape Thompson 

 are of Carboniferous age. Pocks of pre-Carboniferous age 

 doubtless underlie most of the delta deposits immediately 

 west and northwest of the Cape, but the outcrops of these 

 rocks, so far as known, do not extend far south of the channel 

 of the Kukpuk Piver. Along this stream these older rocks, 

 which have been provisionally referred to the Devonian by 

 Collier,§ are well exposed. No fossils have been found in 

 them. They comprise mainly black slates and shales together 

 with sandstones containing some volcanic material with rarely 

 a band of red shale. These older rocks form a belt bordering 

 the Carboniferous limestones on the west to the northwest of 

 the Kukpuk Piver. Although unknown by outcrops, this 

 belt no doubt reaches the coast beneath the shore line and 

 delta deposits to the west of Cape Thompson. 



The rocks exposed in the vicinity of Cape Thompson include 

 both Carboniferous and Mesozoic rocks. The principal struc- 

 tural feature governing the distribution and attitude of the 

 rocks near the Cape is a syncline. The axis of this syncline 

 reaches the coast about two miles southeast of the most north- 



*17th Ann. Kept., Direct. U. S. Geol. Survey, Pt. I, p. 907, 1896. 



f 17th Ann. Kept., Direct. U. S. Geol. Survey, Pt. I, p. 898, 1896. 



\ Geology and Coal Resources of the Cape Lisburne Region, Alaska, Bull. 

 U. S. Geol. Survey, 278, p. 21, 1906. 



§ Collier, A. J., Geology and Coal Resources of the Cape Lisburne Region, 

 Alaska, Bull. U. S. Geol. Survey No. 278, p. 17, 1906. 



