r. i\ blAke on the kimmeeidge glay oe England. 233 



it is as much a clay as at Weymouth. He then called attention to 

 the fact that in France there is a large curve of igneous rocks, 

 roughly parallel to the present outcrop of the English Secondary 

 strata, partly broken through by a mass of Palaeozoic rocks, ex- 

 tending northward from Strasburg through Belgium, and by way 

 of Harwich towards the Cambridgeshire area. He thought that 

 the denudation of these deposits probably furnished the mate- 

 rials of the southern portion of the beds under consideration ; and if 

 so, the stratigraphical sequence becomes intelligible in this way : 

 the Kimmeridge Grit, being sandy, resulted from an elevation of this 

 igneous curve ; and the mass of the Kimmeridge indicated that the 

 Curve was depressed so that the sand did not reach the British area ; 

 while the covering sand shows that it was again upheaved. The 

 bottom sand is in physical continuity with the upper Calcareous 

 Grit ; and the upper sand is similarly continuous with the Portland 

 Sand ; so that he doubted whether any portion of the series is really 

 wanting in England. 



