THE 



GEOLOGICAL MAGAZINE. 



NEW SERIES. DECADE IV. VOL. VIII. 



No. X.— OCTOBER, 1901. 



o:Eaxa-ii<r.A-Xj j^:rtxcil,:e3. 



I. — On some Carboniferous Shale from Siberia. 



By Professor T. Eupert Jones, F.K.S., F.G.S., etc. 



(PLATE XVI.) 



Introduction. 



IN December last M. J. Tolmatschow, Conservator of Geology in 

 the Museum of the Imperial Academy of Sciences in St. Peters- 

 burg, sent for my examination a quantity of two fossiliferous shales 

 from the (Upper ?) Coal - measures in the Basin of Kousnetzk, 

 thinking that specimens of Estheria might be found in them. 



Both the shales came from sections on the Upper Ters Eiver, 

 a right affluent of the Tan River. From one locality (on the 

 Toostooerr River) most of the shale, like that from the other locality 

 (Boogtasch Mountain), is very flaky and friable; but some beds of 

 the former constitute a hard and thick Fosidonomya-shale. 



Both shales are dark in colour, here and there somewhat bitu- 

 minous, and accompanied by a film of coal in one specimen. The 

 surfaces of the shale bear crowds of flattened valves of Anthracomycs 

 and Posidonomyce, often much distorted by pressure, rarely keeping 

 the shell, and usually presenting only a black shiny film. 



Description of Specimens. (Plate XVI.) 



No. I (Figs. 1-4). — This is a right valve, flattened and lengthened 

 by pi'essure ; obliquely ovate, nearly straight above, elliptically 

 rounded below ; higher behind than in front ; extremities rounded ; 

 the posterior more produced than the anterior end, at an angle of 

 25°-30° with the superior border (hinge-line). Concentric lines 

 thin and numerous. 



These features seem to agree with some of Dr. W. Hind's figures 

 of Anthracomya minima (Ludwig), as published in his Mon. Pal. 

 Soc, 1895, pt. ii, p. IIG, pi. xvi, figs. 21, 22, 24-30. Fig. 23 is 

 referred (perhaps wrongly) to a variety of A. l(svis, Dawson, but has 

 much of the appearance of A. minima. 



DECADE IV. — VOL. VIII. — NO. X. 28 



