132 Sheppard : Geology of Brough, East Yorkshire. 



The Oolites represented are the Estuarine Series, the Mille- 

 pore Limestone, and the Great Oolite Clay, of the Lower 

 Oolites ; and the Kellaways Rock, Oxford Clay and Kimmeridge 

 Clay of the Middle and Upper Oolites. 



Let us deal with the Estuarine series first. These beds 

 occur but sparingly, the best sections being in a beck above 

 Elloughton Mill. These show ' hydraulic limestone 2 ft. 6 in. ; 

 yellow sandy clay, 6 ft. ; and calcareous sandstone with fossils, 

 3 in. Another exposure showing 3 ft. of limestone is on the 

 road leading to the mill east of Hotham.'* Mr. Fox-Strangways 

 states! that ' these beds which form the base of the Lower 

 Oolites of the district, are the same as those to which the name 

 ' Basement Beds ' has been given in Lincolnshire, with which 

 they should be correlated in preference to the Lower Estuarine 

 series of the Yorkshire coast.' Unfortunately the remains of 

 plants so characteristic of the latter beds do not occur at 

 Brough. ' 



Next in order comes the Millepore or Cave Oolite. Here 

 certainly we have a more satisfactory deposit to deal with. It 

 occurs in thick beds varying from 20 to 30 feet in depth. The 

 Millepore Oolite is so called from the presence therein of a small 

 branching coral, Cricopora straminea. This fossil appears to be 

 much more plentiful in the lower beds of the Millepore, which 

 are exposed at the western end of the outcrop near South Cave 

 Station. The Millepore limestone is a particularly good example 

 of the 'roe-stone,' and usually shows this structure remarkably 

 well. Exposures of the rock, as might be anticipated, are 

 numerous. Some have been made for lime, others for building 

 material, and still others have been made whilst constructing 

 railways, etc. It rarely happens that this rock is suitable for 

 building purposes, though I believe it has been tried, and it was 

 extensively used in connection with the erection of Beverley 

 Minster. The current-bedding, which is so strongly marked in 

 this series, is a disadvantage from a builder's point of view. 

 Some of the walls in the district have been built of the rock, 

 for example, that in front of Cave Castle, but they do not last 

 long, and it is no uncommon thing to see the mortar standing 

 out from the wall, the intervening limestone having weathered 

 and crumbled away. But geologists must not grumble at this, 

 as these weathered walls are excellent collecting grounds for 

 fossils ! 



* Geol. Surv. Mem., ' Country between York and Hull,' 1886, p. 20. 



floe. cit. p. 19. • 



Naturalist, 



