132 PROCEEDIJfGS OF THE GEOLOGICAL SOCIETY. [Jail. 24, 



2. On the Intr.vliis in Yoricshiee. By the Eov. J. P. Blake, M.A., 

 F.G.S. With an Appendix on some Bivalve Ejttoiiostraca. By 

 Prof. T. EuPERx JoifEs, F.G.S. 



CoiiPARATivELT little attention has been paid to the Lias of York- 

 shii'e for some time past ; and consequently it is behind the Lias of 

 other parts as to our knowledge of it. This is especially the case with 

 the lowest beds — the zones of Ammonites angulatus and Am. pla- 

 norbis — constituting the so-called Infralias, whose presence has as 

 yet been scarcely even recognized. It has long been known that^l?^. 

 angulatus occurs at Kedcar, under the name of A. Redcarensis ; and 

 blocks of stone containing Am. planorhis (syn. erujatus) are thrown 

 up on the coast ; but no section, or list of fossils, has as yet been 

 given of the beds. 



In the present paper I hope chiefly to describe some remarkable 

 sections at Ciiif, near Market-Weighton, where the Infralias is well 

 exposed, and the fauna it contains is large and interesting. But, 

 while I describe this as the Infralias of Yorkshire, I must express 

 my opinion that it does not form part of the typical Yorkshire basin. 

 On glancing at a geological map of this part of England, it will 

 appear probable that there has existed a ridge in Carboniferous- 

 Limestone times, stretching west from a little south of Flamborough 

 Head, which has separated the coal-basin of South Yorkshire from 

 that of Durham, and made a gap in the overlying Permian rocks ; 

 and though the New Bed Sandstone does not appear to be affected by 

 it, all the overlying Jurassic beds are bent round in a curve on its 

 north side, and to the south appear again as the thin end of a series 

 stretching right across England. The beds to the north form the 

 typical Yorkshire basin, while those at Cliff form part of the thin 

 end of the wider-reaching series. Good sections of all the Infra- 

 lias beds in the typical Yorkshire basin are still a desideratum, which 

 I am unable to supply ; but when they are discovered, it must be 

 with the Cliff beds that we first compare them. The nearest beds 

 with which to compare these latter, are those at Marton, near 

 Gainsborough, the list of fossils from which, as given by Mr. Ralph 

 Tate in Quart. Journ. Geol. Soc. vol. xxiii. 1867, proves them to 

 contain a soniowhat similar fauna, as will be seen in the sequel. 



The Infralias beds of Cliff have been briefly described or, rather, 

 noticed by the Eev, W. Norwood, in the ' Geologist,' vol. i. ; but 

 though he recognized their true age, the fossils contained in the 

 beds were so cursorily examined that but little attention has been 

 paid to his paper. Prof. PhiUips also mentions them, but only to 

 state their existence. 



About three miles from Market-AYeighton, on the road to North 

 Cave, at the villages of North and South Cliff, and near the farm of 

 Bielbecks (whose mammalian treasures were described by the Rev, 

 W. V. Harcourt in the ' Phil. Mag.'), are a series of pits opened to 

 extract the Lias clay for marling the adjoining sandy flats. 



In the first of these pits (which for want of any local name must 

 be called " Pit No. 1 ") we have the following section : — 



