202 QUICKSILVER DEPOSITS OF THE PACIFIC SLOPE. 



it is probable that the Horsetown beds of California are represented in 

 those northern localities which have been referred to, it is more especially 

 the equivalent of the fauna of the Knoxville beds that has been recognized 

 as existing there. This recognition is mainly through the identification, 

 among the collections which have been made there, of the AuccIIa, which 

 so strongly characterizes the Knoxville division of the Shasta group in 

 California. Specimens regarded as specifically identical with the form 

 which Mr. Gabb published under the name of Aucdla Pioch'u have been 

 pre.sented to the Survey by Prof Thomas Condon, which he collected at 

 Puget Sound, Washington Territory. These specimens were in bowlders, 

 but they nevertheless indicate tlie existence of an otherwise unknown 

 locality to the north of Oregon. ^Ir. Whiteaves refers to the same species 

 as being abundant at Tatlayoco Lake and other places in British Columbia,' 

 and Professor Eichwald, Dr. P. Fischei", and Dr. White have published 

 forms from diflferent parts of Alaska which the la.st regards as specifically 

 identical with it. 



Among the fossils collected in Alaska by Peter Doroschin, Eichwald - 

 recognized all tlie forms of Aucella which Ke3'serling had published as 

 occurring in Russia, namely, A. roncentrica Fischer, A. mosquensis von 

 Buch, A.^ntUam, nwAA. crussicoUis Keyserling. The last two he considered 

 as only varieties of A. coiicentrica. Dr. Fischer recognized onl}- one species 

 among Pinart's Alaskan collections,^ which he referred to A. concentrica. 



Dr. White also recognized only one species among the collections 

 brought from Alaska by Mr. Dall. Although the specimens were numerous 

 and presented quite a wide variation of form, he regarded them all as repre- 

 senting a variety of Aucella concentrica.* Mr. Whiteaves (loc. cit.) recog- 

 nized only one species among the collections from British Columbia, and 

 this he referred to Amelia mosquensis. 



In the Knoxville beds of California there are two recognizable varieties 

 oi Aucella, which are connected more or less closely by intermediate forms, 



' Seo Traus. Royal Soc. Canada, sec. 4, 18S2, p. 84. 



- SeeGoognost.-palaeont. Bemorkungen iiber die Halbinsel Mangiscblak uud die aleutischeu luseln, 

 18/1, pp. 185-187, PI. XVII. 



^See Voyage i\ la c6t6 nord-ouest de rAuK^riiiiic. par M. Alph.-L. Piuarr, pp. 33-36, PI. A. 

 * See Bull. U. S. (?eol. Survey No. 4, pp. l:!,-14, PI. VI. 



