found in the Sandstone of Ker ridge. 141 



two fragments had been completely ascertained ; or, granting 

 even that this had been done, there would still remain a ques- 

 tion touching the origin of the basin in which these parallel lay- 

 ers of sandstone were deposited. A theory has been hazard- 

 ed by one of my friends, that the hollow might have been 

 induced by the corroding action of running water, which was 

 afterwards filled up by successive deposits of sand, that be- 

 came indurated during the process of consolidation which the 

 rock underwent. This view, however, admits of little to be 

 said in its support. 



The dimensions of the specimen, a drawing of which ac- 

 companies this account, are as follows :* From A to B 13 

 inches ; from C to D, 17 inches ; from A to C, 13^ inches ; 

 from B to D, 14| inches. The diameter of the basin, and of 

 the corresponding section of the spherical body, is 10 inches. 

 All these concretions differ in no respect, as to the nature of 

 the rock of which they are composed, from that of the solid 

 slab in which they are found imbedded. They are of various 

 sizes, some being double the magnitude of the specimen which 

 is figured in the Plate. Nor is the form of the basin, and 

 consequently of the concretion which fills it, always the same. 

 One specimen had a form something between oval and triangu- 

 lar, the recipient basin corresponding to it. 



In the same sandstone where these concretions are found, 

 I detected the fossil remains of gigantic reeds, such as are 

 usually found in coal-fields. 



This is all the description which I have to give of these 

 concretions, and of the circumstances under which they are 

 found ; my object being rather to introduce them to the no- 

 tice of the naturalist, than to offer any hypothesis on their 

 origin, regarding which, I actually feel great lack of inven- 

 tion. Without any further observations, therefore, I shall 

 leave the witch-knots of Kerridge to be unravelled by some 

 more successful geological conjuror than I would confess my- 

 self to be. 



• I am indebted for the specimen to Philip Antrobus, Esq. of Holling- 

 ton, who was so obliging as to point out to me tin site of those concretions. 



