118 Mr. H. T. De la Beche on the Chalk and Sands beneath it, ^c. 



stone alsO;, between the chalk and the sandstone with chert-seams, is much 

 more developed at Beer than at Lyme Regis, and contains much more green- 

 earth. If, therefore, in rocks formed at the same geological epoch, variations 

 such as are here noticed, occur within the space of a few miles, how many 

 points of diflference may we not expect to find in geological equivalents, 

 belonging to countries many thousand miles apart ! 



