Sheppard : The Making of East Yorkshire. 



for the foundations of the ' Howden ' Dam, have been folded, 

 faulted, and packed in a remarkable manner. A is a distinctive 

 bed of Carbonaceous Black Shales ; B and C are two separate 

 Sandstone beds, each about four feet in thickness. 



THE MAKING OF EAST YORKSHIRE. 



THOMAS SHEPPARD, F G.S. 

 (Continued from p. 115.) 



Between the close of the cretaceous period and the next 

 deposit in Holderness is a great gap in our geological history* 

 There is not in Yorkshire, so far as is at present known, a 

 single vestige of that great series of clays and marls and gravels 

 forming the Tertiary system. These rocks in a variety of forms, 

 and with fauna and flora representing a diversity of climatic 

 conditions, accumulated in great thickness in the south-east of 

 England, notably in the London basin, and also on the adjoining 

 continent. What was going on in Yorkshire during this 

 enormous period of time it is difficult to say ; there can be little 

 doubt that some of these deposits were actually formed in this 

 county. 



In many places on the chalk wolds are ' pipes ' or deep 

 hollows in the chalk, '"^ generally only a foot or so wide, but 

 extending to a great depth. It is found that in their lower 

 parts they contain a great number of well-rounded pebbles of 

 quartzite. Similar pebbles also occur in the lowermost layers 

 in the pre-glacial gravels at Hessle and Sewerby, that is, in the 

 deposits resting immediately upon the denuded chalk floor. 

 These pebbles have come from somewhere, they are certainly 

 not derived from the drift beds, and it can only be assumed that 

 in such of these pipes that have been met with during quarrying 

 operations, are preserved traces of a very ancient deposit which 

 must at one time have covered the chalk, but which previous to 

 the glacial period has become entirely swept from the face of 

 the earth in these parts. 



The next stage in the history of this district is evidently the 

 fact that the channel in the chalk plateau which was formed by 

 an immense river running along in a position occupied by the 

 bed of the North Sea, gradually widened, cutting its way 



* See ' The Naturalist,* J904 (Ouartzite Pebbles on the Yorkshire Wolds), 

 pp. 9 and 54. 

 1905 May I. 



