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X. — On the Chalk and Sands beneath it {usually termed Green-sand) in the 

 Vicinity of Lyme Regis, Dorset, and Beer, Devon. 



By H. T. De la BECHE, Esq. P.R., L. and G. S.S., etc. 

 [Read December 16th, 1825,] 



In presenting an account of the manner in which the above rocks occur in 

 the vicinity of Lyme Regis and Beer^ I by no means wish to engage in the 

 discussion which has arisen respecting Green-sand ; but merely to describe 

 the rocks, as they exist in that neighbourhood. At the same time, I consider 

 it as much to be regretted, that some general term is not given to the sands, 

 marls, and clays which occur beneath the Chalk, as has been done in the case 

 of the Oolite formation : the various parts might then be distinguished by 

 different specific names, and there would be no more impropriety in grouping 

 the Green and Ferruginous sands together, than in uniting under one term 

 the various members of the OoUte formation, and distinguishing them by the 

 names of Great and Inferior oolite, Kimmeridge and Oxford clays*, &c. 

 Some such arrangement as this would prevent much uncertainty : for at pre- 

 sent when the term Green-sand is used alone, without further distinction, we 

 may be led to confound two different things. Moreover, we are in want of a 

 general appellation by which to denote these rocks collectively ; for we are 

 not to suppose that all the small divisions that may be made in this collection 

 of sands, marls, and clays in the east of England, can be traced into other and 

 distant countries, where, however, the sands, &c., as a mass may be easily 

 recognised. This cannot be done even in comparatively small distances, as 

 will be seen in the district which I am about to notice ; since the sands come 

 together, and seem more or less to pass into each other ; while the marls and 

 clays, found among them in the east of England, have disappeared. 



The cliffs near Lyme Regis and Beer afford ample opportunities for exami- 

 ning the Chalk and the sands beneath it, usually termed Green-sand, and there 



* Some such name as the Glauco-ferruginous Sand formation might perhaps be applicable ;— 

 part of it has already been termed Glauconie Crayeuse, by M. Brongniart. 



