Eocene and Oligocene coral faunas of Washington
1942; Cambridge University Press; Volume: 16; Issue: 1 Linguagem: Inglês
ISSN
1937-2337
Autores Tópico(s)Coral and Marine Ecosystems Studies
ResumoThirty-three new and four old species of corals and one hydrocoralline are considered. The new species are: Turbinolia quaylei, T. weaveri, Trochocyathus townsendensis, Stephanocyathus holcombensis, Stephanocyathus? sp., Caryophyllia blakeleyensis, C. woodmanensis, C. wynoocheensis, Paracyathus sp. A, P? sp. B, Discotrochus sp., Platycyathus? sp., Flabellum hertleini, Coenocyathus? hannibali, Archohelia weaveri, Sclerhelia? sp., Madracis stewarti, M. crescentensis, Astrangia clarki, Eusmilia bainbridgensis, Colpophyllia reagani, Leptophyllastrea vaughani, Siderastrea washingtonensis, Siderastrea? sp., agaricid sp., Balanophyllia washingtonensis, B. fulleri, Dendrophyllia cowlitzensis, Tubastrea nomlandi, eupsammid sp., Montipora schencki, Astreopora duwamishensis, A. sanjuanensis, and Stylaster milleri. Balanophyllia teglandae Durham is proposed as a new name for B. blakeleyensis Quayle in Tegland (nomen nudum). By a comparison of the fossil coral assemblages with the recent fauna, it is concluded that the middle Eocene Crescent formation had a tropical environment similar to that now at 20? latitude on the Pacific Coast; that the upper Eocene had tropical or subtropical affinities; that the lower Oligocene shale on the Willapa river near Holcomb was deposited in depths of 250 or more meters in a subtropical climate; that the lower Oligocene Quimper sandstone was deposited under subtropical conditions similar to those in the Gulf of California 18? farther south than the fossil occurrence; that the upper Oligocene Blakeley formation had a like habitat although possibly slightly deeper water. Two new formations of lower Oligocene age, separated by an unconformity, are described. The lower is the Townsend shale, apparently the equivalent of the Keasey formation of Oregon; the upper is the Quimper sandstone, correlating with the type Gries Ranch beds and overlapping older rocks of several ages. D URING the course of faunal investigation in the Oligocene and, locally, the underlying Eocene strata of Washington, the writer has collected numerous species of corals. As only three species have been noted previously from these strata, and as important climatic inferences can be made from them, the corals are here described in a separate paper.1 Dr. John W. Wells, of Ohio State University, has kindly examined most of the material here described and has given valuable suggestions as to generic assignments, for which the author makes grateful acknowledgement. As the writer, while working on these faunas, has had occasion to note the occurrence of scattered corals throughout the Tertiary of California, it appears probable that investigation will show the presence of a considerable variety of corals not hitherto noted on the Pacific Coast, and that the 1 Assistance in the preparation of this manuscript was furnished by the personnel of the Works Projects Administration, Official Project No. 65-1-08-62, Unit A-1. 84 faunas of Washington are not unique in this respect. Thirty-four new and four old species are considered. They were found in formations ranging in age from early middle Eocene (Capay) to late Oligocene. Fragmentary material from several localities indicates that numerous species are yet to be collected and described. Of the species referred to, 22 are colonial and 16 are solitary forms. All of the coral localities except 7162, A-78, A-1810 (=C.A.S. 912), and N.P. 51, occur between 47?30' and 49? north latitude, 18? to 20? farther north than most corals are found living on the Pacific Coast. The excepted localities are all north of 46?30' latitude. The ecology of the recent corals, in certain aspects as least, is better known than that of many marine organisms. Vaughan (1940, pp. 458-464) has recently reviewed the available data and given references. Many genera are limited both thermally and bathymetrically in their recent distribution. Although some of the genera ranging throughout the Tertiary may have had a This content downloaded from 207.46.13.178 on Wed, 15 Jun 2016 06:43:22 UTC All use subject to http://about.jstor.org/terms CORAL FAUNAS OF WASHINGTON different distribution in the past than in the recent faunas, it seems that the average environment of the fossil assemblage should approximate that of like recent assemblages. Upon this basis, the coral assemblages from the different localities have been compared with similar modern faunas, and the probable past environment postulated. The results of these comparisons are as follows:
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