m DESCRIPTION OF THE STRATA. 



agree in having the same schistose or slatj' structure, easily splitting 

 into thin lamina, from whence they have the name schistus or schist. 

 They possess various degrees of induration, but are all comparatively 

 soft, scarcely deserving to be denominated rocks. 



The shale or schist that succeeds the chalk, which we call the 

 UPPER SHALE, as being higher in geological situation than any other 

 shale bed in the district, is of the argillaceous or alviminous kind, or 

 what is frequently termed slate-clay.* This bed is seen to most ad- 

 vantage on the shore below Speeton, rising behind the chalk, to the 

 height of 150 feet or upwards, and extending along the shore about 

 half a mile. In some parts, the shale is concealed by, or blended 

 with, the alluvial covering; but at its junction with the chalk, it is 

 quite bare and distinct. 



Had we no other means of ascertaining the relative situation of 

 the chalk and the shale, than the appearances presented at their 

 junction in the Speeton cliffs, we might suppose that, instead of the 

 one running beneath the other, they are only placed in juxtaposition: 

 for, as may be seen in the Section (where h denotes the chalk and c 

 the upper shale ) , the shale is too elevated to be considered as run- 

 ning beneath the chalk, were they in their original position. A deep 

 channel worn by a rivulet separates between them, and were either 

 or both extended a few yards, in the line of their dip, they would 

 abut against one another, but the shale could not go under the chalk, 

 except at the very lowest part of the shale bed. We have the best 

 ineans of knowing, however, that the shale does run under the chalk, 

 and lies under it in a conformable position; for not only do we find 

 it cropping out ( as the phrase is ) from under the chalk, at Knapton, 

 Thorpe-Basset, Settrington, and other places, but its situation has 



* Some also apply to il the term clay-slate, but that name ought to be appropriated to llie 

 liard clay-slate used for roofing. 



