390 



couver Coal Co.'s mine, Nanaimo, and from ten to twelve miles up the 

 Nanaimo River, by Mr. Harvey ; also at Brennan Creek, near Wellington, 

 by the Rev. G. W. Taylor. Similar specimens had previously been collected 

 at Hornby Island by Mr. Harvey in 1894, and at the Sucia Islands by 

 Dr. Newcombe in 1894 or 1896. 



In the first volume of the American Joui'nal of Conchology, published 

 in 1865, Mr. Conrad says of JV. truncata that " two species are evidently 

 confounded under this name. Mr. Gabb should " (he says) " have figured 

 a specimen from each division, as he has done in Amauropsis alveata." 



Much more recently, in 1898, Dr. Dall says that "an examination of 

 undoubted Cretaceous specimens of If. truncata shows that the species 

 differs from the Tertiary forms by its more impressed escutcheon, its finer 

 and more delicate divaricate sculpture, and its more prominent close set 

 regular and even concentric sculpture. Those I have seen are also 

 smaller."* 



In a letter received in March, 1902, Dr. Stanton writes that he "doubts 

 whether the Tejon specimens are different from the Chico ones," but that 

 in any event the name N. truncata should be applied to the Chico form, 

 because the type specimens are from Chico localities." 



YOLDIA DIMINUTIVA. (N. Sp.) 



Plate 47, fig. 2. 



Shell very small, inequilateral, moderately convex, slightly produced 

 and narrowly rounded in front, abruptly pointed and a little longer behind ; 

 length nearly twice the maximum height ; beaks small, placed a little in 

 advance of the midlength. 



Surface apparently concentrically striated. 



Length, 4 • 7 mm. ; greatest height, 2 • 9 mm. 



Roof of coal, New Vancouver Coal Co's mine, Nanaimo, W. Harvey, 

 1901 : a cast of the interior of a left valve with a small portion of the 

 test preserved. This little shell differs chiefly from the Leda translucida, 

 of the Californian Tertiary, as described and figured by Gabb, in its very 

 diminutive size, the figured specimen of L. translucida being represented 

 as 12 mm. long. The genus Leda, however, is now restricted to shells 

 with a "long tapered bicarinate rostrum," and Y. diminutiva is obviously 

 congeneric with the Yoldia microdonta and Y. ventricosa of Meek, from 



■^ Transactions of the Wagner Free Institute of Science, Philadelphia, vol. ill, pt. iv, 

 p. 573. 



