Sheppard : Geology of Brough, East Yorkshire. 131 



not so plentiful here the pit is of interest, as the beds have been 

 contorted and crumpled in a remarkable manner ; resembling 

 two or three W's. A depression on the top of the hill, just 

 above the pit, seems to suggest a fault or slight displacement, 

 though at first glance the crumplings are very suggestive of 

 glacial action. A stream of water issues from the shales near 

 the entrance to this pit — the rusty appearance of the rocks 

 adjacent betraying its chalybeate properties. But in addition to 

 the superabundance of iron in the water there is apparently an 

 excess of lime, as large slabs of petrified moss, reeds, etc. , can 

 be picked up in the bottom of the stream. In one place where 

 the water flows over a slight ridge huge masses of calcareous 

 tufa occur, in steps one above another. These readily come to 

 pieces under the blows of the hammer and reveal an enormous 

 thickness of encrusted moss. 



Further northward still and we reach the sections described 

 by Messrs. Tate and Blake in their work on ' The Yorkshire 

 Lias,' 1876, pp. 38-39. These occur on the sides of a road which 

 crosses the hill, and fossils are fairly plentiful. Amongst them 

 are some peculiar deformed Ostrea, which on their outer surface 

 have the impression of an ammonite. These, Mr. P. F. Kendall 

 suggests, evidently represent the upper valves of the Ostrea, 

 the lower valves of which have adhered to the shells, probably 

 cast shells, of Ammonites pldnorbis. So far, however, though 

 plenty of loose valves have been obtained, in not a single case has 

 an ammonite been secured with the valve of an Ostrea attached. 



The Middle Lias does occur in the neighbourhood, but that 

 is about all that can be said of it. No good sections are now 

 visible, though some small ones were opened out during the 

 construction of the Hull and Barnsley Railway in the early 

 Eighties — the beds of the Ammonites capricornus and Ammonites 

 spinatus zones being traced. Slabs of this rock are visible on 

 the slopes on the line side between North and South Cave. 



The Upper Lias is even still worse as regards sections ; in 

 fact, I know of no exposure worthy of the name. The beds are 

 very thin here, only a very narrow band being mapped, and this 

 I believe on the evidence of sections on drain sides, in well- 

 shafts, etc. 



We now reach the Oolites. These form by far the most 

 important feature of the district, and no one can speak on this 

 subject without referring to Mr. Alfred Harker's short but pithy 

 paper on the 4 Oolites of the Cave District,' which appeared in 

 the 'Naturalist' for May 1SS5, pp. 229-232. 

 19m May ~ • 



