﻿434 



STRATIGRAPHICAL DISTRIBUTION OF 



From the above Tables, it appears that the English Oolitic rocks are known at present 

 to contain 16G species of fossil Echinodermata, of which 119 species belong to the Order 

 Echinoidea ; 18 species to the Order Asteroidea ; 7 species to the Order Ophiurotdea ; 

 and 22 to the Order Crinoidea. All the species belonging to the families Cidarid;e, 



HeMICIDARIDjE, DlADEMADiE, ECHINID^E, SaLENIADJS, ECHINOCONID^E, EcHINOBRISSIDjE, 



CollyritiDjE, Echinanthid^e, and Echinolampid^, have been figured in this work. 



The Asteroidea, Ophiuroidea, and Crinoidea, will form the subject of a second 

 Monograph. An analysis of the Tables gives the following distribution of the species in 

 each stage : 



Lower Lias 



. 10 Sp 



ecies. 



Middle Lias . 



. 17 



>> 



Upper Lias 



. 12 





Inferior Oolite 



. 49 



» 



Fuller's Earth 



1 



>> 



Stonesfield Slate 



. 8 



>> 



Great Oolite 



. 28 



>» 



Bradford Clay 



.9 



ii 



Forest Marble 



. 8 





Cornbrash . 



. 21 



ii 



Oxford Clay and Kelloway 



. 



>> 



Lower Calcareous Grit . 



. 11 



ii 



Coral llag 



. 24 



)> 



Upper Calcareous Grit . 



? 



9 > 



Kimmeridge Clay . 



. 4 



if 



Portland Sand 



1 



)l 



Portland Oolite 



1 



>> 



Marine Purbeck Beds . 



1 



>> 



The Lias forms appear to be special to the three subdivisions of that formation, so well 

 characterised by the species of Ammonites which indicate these three zones of Liassic life. 

 The Inferior Oolite contains forty-nine species, of which forty-three are Echinoidea, 

 three Asteroidea, one Ophiuroidea, and two Crinoidea ; of these, ten species 

 extend into the Great Oolite, and nine species pass into the Cornbrash ; the Inferior 

 Oolite has therefore thirty species which up to this time have not been found in any 

 other formation ; all the species from the Lias to the Cornbrash inclusive became extinct 

 before the deposition of the Kelloway rock and Oxford clay. The Fuller's earth has 

 yielded one species, and the Stonesfield slate contains eight species, several of which are 

 special to this fissile rock. The Great Oolite has yielded twenty-eight species, of which 

 ten extend into the Cornbrash, fourteen are special to the Great Oolite stage, and four are 

 common to the different stages of the lower division of the Oolites. The nine species 

 of the Bradford clay are mostly common to this argillaceous bed, and the Great Oolite 

 limestone on which it rests. The Forest Marble contains eight species, of which four are 

 common to this rock and the Cornbrash, which contains twenty-one species, many of 



