Sir N. Yermolof — Diatom Earth in California. 271 



Mr. R. B. Newton, F.G.S., and Mr. H. A. Allen, F.G.S., for kind 

 sympathy and facilities, and Professor G. A. J. Cole, F.R.S., and 

 Mr. H. Woods, F.R.S., for kindly answering queries as to records 

 of Lingula from the Chalk of Ireland and Britain respectively. 



The Diatomaceous Earth of Lompoc, Santa Barbara Co., 



California. 



By Sir Nicholas Yermolopf, K.C.B., K.C.V.O., F.L.S. ; with a 

 Prefatory Note by Dr. A. Smith Woodward, F.R.S, 



LAST year Mr. J. L. Bosqui gave to the Geological Department 

 of the British Museum part of a fossil shoal of herrings found 

 in a marine deposit of diatoms, now being worked for commercial 

 purposes as " celite " in Santa Barbara Co., CaHfornia. The species 

 represented has since been named Xyne grex by Professors Jordan 

 and Gilbert,' who exclude it from the genus Cliq^a on account of 

 its thicker enamelled scales, enamelled opercular bones, and strong 

 ventral scutes. The matrix, examined under the microscope, proved 

 to consist so completely of diatoms and other siliceous organisms 

 that it seemed desirable to submit them also to special examination. 

 I was therefore fortunate in enlisting the services of Sir Nicholas 

 Yermolofi, whose extended studies of such organisms make his 

 determination and discussion of these new fossils of particular value. 

 His notes form an interesting supplement to the following short 

 account of the deposit, which was given by Dr. Frank M. Anderson 

 to Professor Jordan (op. cit., p. 14) : — 



" The white shales about Shorb and El Modena are well known 

 to be diatomaceous, and often considerable bodies of these rocks, 

 that is a considerable thickness of them, is comparatively free from 

 grit. I have been accustomed to regard these shales as of Puente 

 age, as I believe they have been classified by Dr. Arnold, and I have 

 been of the opinion that the Puente formation is middle or lower 

 Miocene in age, and is the equivalent of the Monterey, taken in that 

 sense. 



" The Puente group is certainly not the base of the Miocene in 

 the region about Los Angeles, and in the localities mentioned in 

 your letter, namely Shorb and El Modena, the beds are near the 

 middle or a little below the middle of the Miocene section. 



" I presume you have some information regarding the large number 

 of fossil fishes found in the diatomaceous beds of near the same 

 horizon some 3 or 4 miles south of Lompoc, Santa Barbara County. 

 The rock here is almost entirely made of diatom material some 600 

 to 800 feet thick.' 



' D. S. -Jordan and J. Z. Gilbert, Fossil Fishes of Southern CaHfornia (Leland 

 Stanford Junior University Publications, University Series, 1919), p. 25, with 

 figures. 



^ The maximum thickness was subsequently stated to be 1,400 feet by 

 .Jordan & Gilbert, Fossil Fishes of the Diatow Beds of Lompoc, California 

 (loc. cit., 1920, p. 5). 



