t 



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University of California. 



[Vol. 2. 



tions seem to indicate. Trigonia evansana, Mcretrix varians, and 

 Corbula traskii apparently range throughout the Chico beds. 



"A few of the names in the above list deserve a word of special 

 comment. 



" ' Mytilus cf. lanceolatus Sowerby. Represented by a single small 

 specimen that seems to be identical with form from Skidegate Inlet, 

 Queen Charlotte Islands, doubtfully referred by Whiteaves to M. 

 lanceolatus. It also occurs at Texas Springs, California, and Jack- 

 sonville, Oregon. 



" Trigonia leana Gabb. This is the species figured by Gabb in 

 Paleontology of California as T. gibboniana Lea. He afterward 

 considered it a new species and named it T. leana, but there is still 

 reason to doubt whether it is really distinct from T. tryoniana Gabb 

 which was described from an imperfect specimen that had lost the 

 outer layer of shell. Some of the shells in the present collection 

 have lost the outer layer of shell and thus acquired such a different 

 aspect that they were at first considered a different species. T. 

 leana occurs in the lower Chico beds at Jacksonville, Crooked 

 River, Grave Creek, and other localities in Oregon, and at many 

 places in California, including Texas Springs and Horsetown. The 

 fossils from Skidegate Inlet, listed by Whiteaves as "7! tryoniana?" 

 probably belong to T. leana, if it is really distinct from the typical 

 T. tryoniana. If not, the latter name has priority, and should be 

 used for the species. 



" Meekiaradiata Gabb ? This species is represented by a number 

 of well-preserved specimens differing materially from the figures of 

 Gabb's type in that they attain a much larger size, being as large 

 as M. sella Gabb, and have the whole surface covered with radiating 

 sculpture. Specimens of smaller size but with precisely similar 

 sculpture have been collected at Texas Springs, California, and the 

 same form occurs at Grave Creek, Oregon, associated with others 

 in which the surface is partly exfoliated and the radiating sculpture 

 is very obscure. These facts lead to the suspicion that M. radiata 

 was based on the miniature or depauperate specimens, in which the 

 surface was not perfectly preserved, and I have, therefore, not 

 ventured to separate these larger well-preserved specimens as a 

 distinct species. 



