134 ALASKA GEOLOGY 



the tubes occur contain no other evidence of either animal or vege- 

 table remains. 



Dr. W. H. Dall collected the first specimens of this fossil, and men- 

 tions it in his Report on Coal and Lignite of Alaska (Seventeenth An- 

 nual Report United States Geological Survey, part i, page 872) . He 

 speaks of it as " a singular organism like a flattened Dentalium, but 

 probably a worm tube." 



Named for Dr. Charles Palache, one of the geologists of the Expe- 

 dition. 



Localities. Most of the specimens are from Pogibshi Island, op- 

 posite the village of Kadiak. Others came from near Hidden Glacier, 

 at Russell Fiord of Yakutat Bay, and from Woody Island, near the sta- 

 tion of the North American Commercial Company, while a single ex- 

 ample was secured from a boulder in the moraine of Columbia Glacier, 

 Prince William Sound. 



Collectors. -W. H. Dall, G. K. Gilbert, B. K. Emerson, Charles 

 Palache. 



MOLLUSCA 



PELECYPODA 



Genus Inoceramya gen. nov. 



Shell resembling that of a Posidonomya, apparently equivalve, thin, 

 compressed, concentrically waved ; hinge margin straight, long, eden- 

 tulous, but bearing on its central part several small but long vertical 

 ligamentary pits, and behind these, possibly to the end of the hinge, 

 numerous shorter and gradually diminishing pits ; post-cardinal region 

 compressed, obtusely wing-like, distinguished externally from the con- 

 centrically waved body of the valve by finer and somewhat differently 

 directed striation and internally by a rib-like thickening extending 

 obliquely backward from the beaks toward the middle of the dorsal 

 half of the posterior margin ; anterior part of hinge unknown ; beaks 

 subcentral, not large. 



The systematic position of this genus may be said to be intermediate 

 between Posidonomya Bronn and Inoceramus Sowerby, though it has 

 certain characters not possessed by either of the two genera mentioned. 

 From the former it is distinguished by having ligamentary pits ; 

 from the latter by the absence of the prismatic inner shell layer that is 

 so highly characteristic of Sowerby's genus, and in having the hinge 

 plate wider and the ligamentary pits longer in the region of the beaks. 

 Continuing the comparison, we find that the characters pertaining to 

 the wing-like post-cardinal region of the new genus are not present in 

 either of the old genera. 



