320 Scientific Intelligence. 



II. Geology and Natural History. 



1. Contributions to the Cretaceous Paleontology of the Pacific- 

 Coast: The Fauna of the Knoxville JBeds ; by T. W. Stanton. 

 (Bulletin U. S. Geological Survey, No. 133.) 132 pp., 20 plate.% 

 Washington, 1895 [issued Feb. 3, 1896]. Abstract by the author. 

 — The Knoxville beds as described in this paper form the lowest 

 division of the Lower Cretaceous section in California, and are 

 found in the Coast ranges irom San Luis Obispo County, Cal., 

 (near latitude 35°) on the south to the neighborhood of Seattle, 

 Washington, on the north, though they are not continuously 

 exposed throughout that distance. The name was first applied in 

 1885 by Messrs. White and Becker to the Aucella-bearing portion 

 of the ill-defined Shasta group. Since then the beds have been 

 studied more in detail, especially by Mr. J. S. Diller, and a resume 

 of his stratigraphic results is given together with the author's 

 observations made during portions of two field seasons spent in 

 the most important areas. 



Lithologically the beds consist of a series of dark clay shales 

 alternating with sandstones, usually in thin beds, with local deposits 

 of heavy conglomerate and more rarely small limestone masses. 

 The thickness is very great, always several thousand feet and, 

 according to one of Mr. Diller's measured sections, reaching a 

 maximum of nearly 20,000 feet in Tehama County, Cal., where 

 the series is best developed both faunally and lithologically. 



The underlying formations have not been very definitely deter- 

 mined owing to the fact that they are usually unfossiliferous and 

 frequently more or less obscured by metamorphism and by the 

 intrusion of igneous rocks. The evidence tends to prove that the 

 Knoxville rests on rocks varying in age from Carboniferous to 

 probably Upper Jurassic. The Horsetown beds which rest con- 

 formably on the Knoxville are, in part at least, referable to the 

 Gault. 



The invertebrate fauna as now known consists of 17 species 

 and varieties, of which 50 species and one genus (Cardiniopsis) 

 are described as new. Most of these are rare, having been found 

 at only one or two localities, but the several forms of Aucella are 

 very abundant, often filling the rocks and occurring at many hori- 

 zons. All but 7 of the species are Mollusca, including 33 species 

 of Pelecypoda, 1 of Scaphopoda, 18 of Gastropoda, and 18 of 

 Cephalopoda, of which 15 are Ammonoids and 3 are Belemnites. 

 The ammonites belong to the genera Phylloceras, Lytoceras, Des- 

 moceras, Olcostephanus and Hoplites, the last being especially 

 well represented. The other seven species include 5 Brachiopoda 

 and two Echinodermata. 



As a result of the study of the fauna the Knoxville beds are 

 referred to the Lower Cretaceous and are regarded as later than 

 the Mariposa beds of the Sierra Nevada, which are also Aucella- 

 bearing but of Jurassic age. 



