C. J. A. Meyer — Chloritic Marl and Tipper Greensand. 549 



the term "Chloritic Marl" has been always subsequently applied to 

 the uj)per of these two beds — the " Scaphites-bed " or actual base-bed 

 of the Chalk Marl. Such, however, is not the case. In Mem. Geol. 

 Survey, Dec. iii. page 4, Professor Forbes, referring to Chloritic 

 Marl, says : — " It is a remarkable stratum abounding in peculiar 

 fossils, and containing numerous Echinoderms. I have examined it 

 and found the small variety of Galerites castanea plentifully near 

 the village of Chaldon, in Dorsetshii'e." " Both larger and smaller 

 varieties occur near Warminster." Now the small variety of Galer- 

 ites castanea, in the Isle of Wight, belongs especially to the lower 

 half of the Chloritic Marl of Ibbetson. 



It appears, therefore, that the term "Chloritic Marl" as first 

 applied embraced two sets of strata with, in time at least, a gap 

 between them. 



In the light of recent researches this fact has become more evident 

 than it could possibly have been in former times. One knows now 

 that the Cretaceous rocks do not exhibit in any one locality a perfect 

 series. Here and there some bed is wanting — rarely indeed without 

 some sign or indication of the fact. Pebble-beds, grit-beds, layers of 

 phosphatic nodules, lines of erosion, and sudden changes of fauna, all 

 point usually to missing strata. And in no part of the Cretaceous 

 rocks is this, perhaps, more frequently evident than between the 

 Upper Gault and the Chalk with Inoceramus labiatus. To illustrate 

 this one need but follow the, already, partly recognized life-zones of 

 the intermediate strata. For, thanks to Hebert, Barrels, and other 

 diligent observers, it is now well-nigh established that beneath the 

 Chalk with Inoceramus labiatus one finds, or ought to find, the 

 following life-zones : — 



g. Zone of Belemnites plenus. 



f. „ Holaster subglobosiis. 



e. „ Scaphites cequalis = The z.one of Ammonites laticlavius, of Barrois. 



d. „ Holaster nodulosus (of Hebert). | ^ ^-^^ ^^^^ ^^ p^^^^^^ ^^ 



b. ,, Ostrea vesiculosa, and Janira quadricostata ) 



a. ,, Exogyra conica and Cardiaster fossarius = The zone oi Ammonites in- 



Jiatus (in part) , of Barrois. 



But, at Folkestone, zones a. b. c. d. are missing. At Cambridge 

 a. b. c. d. and e. are missing. While near Beer Head g. in places 

 rests on d. And, probably, because the bases of zones d. e. f. g. 

 contain green grains and remanie phosphatic fossils in some localities, 

 the term '•' Chloritic Marl " has been at various times applied to each 

 and all. Nor is this surprising. For one finds that in France and 

 Belgium the, to some extent, equivalent terms " Tourtia " and 

 " Marne Glauconieuse " have been also not infrequently applied to 

 beds of various ages. 



That the term " Chloritic Marl " is then, and has always been, a 

 bad one, is clear enough. Yet this in no way affects the correctness 

 of my reference of beds 10 to 12 of the Devon sections to Chloritic 

 Marl.^ These beds embrace the Chloritic Marl of the Isle of Wight 

 and more besides. The phosphatic fossils in bed 13 of Beer Head 



1 Quart. Journ. Geol, Soc. vol. xxx. p. 385. 



