fossils 259 



identified by the writer at a number of localities to the south, and forms 

 the westernmost of the lithologic belts which have been referred to. 



Reference has already been made to a coral which was found on the 

 moraine of Dirt glacier by Professor Stevenson. The following is quoted 

 from Professor Stevenson's description : * 



" The Dirt glacier or first western tributary of the Muir must head up against an 

 outcrop of this limestone, for one of the passengers on our vessel picked up a form 

 like Acervularia, which, taken in connection with some Leperditia obtained by Mr 

 Cushing in 1890 (Drake island), tends to show that the limestone (Glacier Bay 

 limestone) is not younger than Middle Devonian." 



Through the courtesy of Professor Williams, Mr Schuchert was enabled 

 to examine, too, the coral secured by Professor Stevenson, and he reports 

 as follows : 



"Later this coral was sent to Professor Williams, and Cushing reports that he 

 identified it as a Lonsdalela, ' and regards it as demonstrative of the Carboniferous 

 age of the horizon whence it came.' 



"I agree with Stevenson that the coral in question is an Acervularia, since it has 

 no columella, as is demanded for species of Lonsdalela. It is a species near A. 

 davidsoni, a coral so characteristic of the Middle Devonian of the Mississippi valley. 

 It may prove to be a new species when sections are made. The genus Acervularia, 

 however, is unknown above the Devonian. Another Acervularia is known from 

 the Mackenzie River country (Cyathophyllum arcticum Meek), so that the genus 

 may be expected to turn up elsewhere in the far north. 



"Since Acervularia of the type A. davidsoni is so characteristic of : the Middle 

 Devonian, it seems safe to assume that beds of this age occur in the Glacier Bay 

 region, and that it is the same general horizon discovered the past summer by 

 Mr Brooks at Long Island, Kasaan bay, Prince of Wales island." 



According to Mr Schuchert, then, this coral is from a bed which is an 

 entirely different horizon from the limestones at Drake island, which he 

 determined as Silurian. This evidence points to the conclusion that 

 there is a younger limestone in the Glacier Bay region which is of 

 Devonian age. This limestone, however, has not been identified at any 

 other locality in the northern part of the region under discussion. 



Ln the southern islands of the Alexander archipelago Devonian beds 

 have been found at.several localities. Mr Schuchert identified as Devo- 

 nian f some fossils contained in a white crystalline limestone collected 

 at Saginaw bay, Kuiu island, by Mr Brightman. It is interesting to 

 note that some fragments of sandstone from this same locality contain 

 Upper Carboniferous fossils. This is the only locality in southeastern 

 Alaska where this horizon has been identified. 



*The Scottish Geog. Mag., vol. ix, 1893, p. 70. 



f Charles Schuchert : " Report on Paleozoic Fossils from Alaska." Appendix ii, Coals and Lig- 

 nites of Alaska, Seventeenth Ann. Rept., part i, p. 902. 



