340 /:'. .)/. Kindle — Faunal Succession in the 



sonic of the limestones which have heen correlated with the 

 Port Clarence into more concise cartographic units. The most 

 recent detailed work on the geology of this part of Alaska has 

 been done by Smith and Eakin* on an area in the southeastern 

 part of the Seward Peninsula. Three of the limestone areas 

 without the York Mountain region which have been correlated 

 with the Port Clarence have, however, furnished fossils which 

 show that they are of distinctly later age than the faunas 

 occurring in the typical Port CJarence. These outside lime- 

 stone areas, which are known to be distinct from the Port 

 Clarence and of later age, are known as Baldy Mountain, 

 Devil Mountain, and White Mountain. Before considering 

 the data relating to the age of these areas which have been 

 mapped as Port Clarence beyond the York Mountains, the 

 evidence showing the composite character of the faunae in 

 the Port Clarence as found in the type region will be pre- 

 sented. The fossils collected by the writer in the York 

 Mountain region were obtained at somewhat widely distrib- 

 uted stations. These were selected with the intention of deter- 

 mining the thickness of the beds to be ascribed to the different 

 faunas in the limestone series, but the amount of time allotted 

 to the work, together with the uncertainty regarding some of 

 the structural features involved in the present orientation of 

 the limestones, made it impracticable to carry out the original 

 intention. Hence the more salient facts concerning the fauna 

 are presented without such stratigraphic detail. 



Faunas of the Port Clarence. — The oldest fauna which 

 was found in the Port Clarence limestone occurs in the lime- 

 stones exposed about the head of Tin Creek and to the south- 

 east of Cassiterite Creek. Two fossiliferous zones were found 

 in this vicinity separated by several hundred feet of apparently 

 barren limestones. In one of these, station 'No. 8 at the head 

 of the north fork of Tin Creek, fossils occur in abundance in a 

 single thin band of limestone which seems to lie in the midst 

 of barren beds at an elevation of about 2,000 feet A. T. This 

 fauna was referred to Mr. E. O. Ulrich, whose determination 

 of the species is as follows : 



" Eoorthis sp. or var. nov. Closely allied to E. wichitensis and 

 E. remnieha texana of Walcott. These and all similar species of 

 this genus known to me occur in the upper part of Cambrian and 

 in the basal part of beds immediately following it. Iluenella 

 texana Walcott ? Associated with Eoorthis remnieha texana in 

 the Upper Cambrian in Central Texas." f 



!%To the northward of the zone holding this fauna the blue-gray 

 limestones which are supposed to lie below it stratigraphically 



* Bull. U. S. Geol. Survey No. 449. 

 f Letter to the writer, Mar. 10, 1909. 



