The Marsupites Chalk of Brighton. 



13 



a thickness of 58 feet of chalk, the whole of which he assigns to his 

 zone of Marsupites, and further to his Marsupites hand as Uintacrinus 

 was not found in it, hut he notes that Uintacrinus has been found on 

 the reefs. These points have, as far as I know, stood unchallenged 

 hitherto, but I am unable to reconcile them with my experience. 



The marl band which Dr. Rowe took as the base of the old zone of 

 A. quadratas (op. cit., p. 340) can be identified beyond all question 

 as the one which in the August number of this Magazine, p. 363, 

 I placed 15^ feet up in the subzone of Echinocorys scutatus, 

 var. depressus. Below it I have measured the following section in 

 which my own classification is indicated. 



Chalk of the Brighton Cliffs below the (old) Zone of A. quadratus. 



£ 



Marl band (Dr. Eowe's base of (old) zone of ft. in. 

 A. quadratus). 



(8. Chalk 



Marl band. 



[7. Chalk 



Marl band. 

 1 6. Chalk without any crinoid brachials or plates 

 '5. Chalk with a number of brachials and one plate 

 Very thin and rather uncertain marl band. 

 Chalk with crinoid brachials and curious plates 



Strong marl band. 

 Chalk with Marsupites . . . . . 15 6 



Parting with traces of marl. 

 Chalk with Marsupites . . . . 10 



\ Strong marl band. 



Chalk with Marsupites 8 3 



Pair of marl bands with intervening chalk 1 6 

 V Chalk with Marsupites ..... 9 6 



Parting and weak marl seam. 



Hard chalk without crinoid remains . . . 



Thick flint seam. 

 Chalk with one crinoid brachial . . . . 3 



Marl seam. 

 Chalk with Uintacrinus ..... 4 



Marl seam. 

 Chalk with Uintacrinus ..... 5 3 



Marl seam. 

 Chalk with Uintacrinus ..... 6 



H 



Flint seam determining the general reef level at 

 Black Bock. 



Zone of 0. pilula 



, , Marsupites , 

 Uintacrinus band 



ft. in. 

 14 6 

 52 9 

 14 9 



82 



ft. in. 



6 



5 



3 6 



1 



7 



44 9 

 2 



12 9 



82 



It will be seen that I found 82 feet of chalk exposed in the cliff, 

 against Dr. Rowe's measurement of 58 feet, and a considerable 

 thickness of the Uintacrinus band where he found none. 



The whole of Bed 1 is exposed for a distance of some 150 feet from 



