CRETACEOUS. 



351 



CRETACEOUS. 



Fig. 56. — Chalk Cliff at Ballard Head, North of Swanage. 



The Cretaceous system is composed of a series of rocks 

 that exhibit varied phases, both in their Hthological characters 

 and method of formation ; the series is mainly composed of 

 sands and clays, but it includes the Chalk, and on that 

 account the name was applied by Dr. W. H. Fitton.^ The 

 following are the main divisions in this system : — 



y g^ ( Chalk 

 PP J Upper Greensand 



Cretaceous, j n \^ 



Lower ( Lower Greensand 

 Cretaceous. ( Wealden Beds 



Neocomian 

 of some authors. 



Considerable difference of opinion has been expressed regarding 

 the nomenclature and the grouping of the beds ; but on the whole 

 it appears best to divide them into an upper and a lower series as 

 above indicated. For this system the term Anglian was proposed 

 by Prof. Hughes in 1879.^ 



The term Neocomian, introduced into England by Mr. Godwin- Austen in 1843,^ 

 has been generally used as a synonym for our Lower Cretaceous strata. It was 



1 Ann. Phil. (2), viii. 382 ; see also pp. 365, 458, 

 ^ Proc. Cambridge Phil. Soc. iii. plate vi. 

 3 Proc. G. S. iv, 170 ; Q. J. vi. 478. 



