﻿A. J. JuJies Browne — On the Up]per Greensand, etc. 361 



of 75 ft. Nos. 8 and 9 he parallels with his Etage C, and numbers 

 10, 11, 12 he agrees with Mr. Meyer in referring to the fossiliferous 

 portion of the Warminster beds ; thus giving to the whole zone of 

 P. asper a thickness of 21 feet. Nos. 13 and 14, called Chalk Marl 

 by Mr. Meyer, he correlates with the Chloritic Marl, though ad- 

 mitting the possibility of the latter bed being the attenuated repre- 

 sentative of his Holaster subglobosus zone or Chalk Marl. 



He proceeds to trace these several stages through Devon and 

 Dorset, but we must not forget that Mr. De Kance had accurately 

 described them in 1874, and had even given the same names to two 

 of the groups ; had he indeed ventured on a more extended corre- 

 lation of the zones, he would perhaps have anticipated Dr. Barrels' 

 division of the Upper Greensand; referring to the tables before 

 given, it is evident that zone I. of De Eance = Etage E (Chloritic 

 Marl), that zone II. =: Etages D and E (Fecten asper), zone III. = 

 Etage B {Ex. conica), while the Fox-mould and Cowstones repre- 

 sent Etage A of the Am. imflatus zone. 



The section on the northern side of Swanage Bay has also been 

 recently described by Mr. H. G. Fordham,^' who divides the Upper 

 Greensand into its local component beds ; he informs me that he 

 would assimilate the first three of these, with a total thickness of 26 

 feet, to the P. asper zone, and refer the remaining 40 or 50 feet to 

 the Am. inflatus zone of Dr. Barrels. 



Eegarding the Chloritic Marl he says that its junction with the 

 underlying Upper Greensand is irregular but well marked, and 

 further on, "I have used the term^ Chloritic Marl to signify the lowest 

 bed of the Chalk Marl, which is characterized by the presence of 

 glauconitic grains, and a Chalk Marl fauna, mixed with many derived 

 phosphatic casts of fossils." Its thickness he gives as 4 feet, and 

 correlates it with the Cambridge phosphate bed and No. 13 of Mr. 

 Meyer's section. 



Concluding Bemarhs. — As I conceive we now possess a knowledge 

 of the true order and succession of the Greensand beds above the 

 Gault, together with a more accurate conception of their character, 

 contents, and extent, it only remains for me to make a few remarks 

 on the application of the terms Chloritic Marl and Upper Greensand, 

 and to indicate one or two points that seem to require still further 

 investigation. 



From the foregoing sectional evidence I think it is clear that no 

 break occurs in the series from the base of the Gault upwards till 

 we reach the so-called Chloritic Marl, and that here there is a well- 

 marked discontinuity, both stratigraphical and palasontological. 

 The line of separation and slight erosion at its base in the south- 

 west becomes more decided when traced to the north-east, and the 

 small indigenous fauna, when the numerous derived fossils are 

 separated from it, is found to differ very little from that of the 

 Chalk-marl, and to be quite distinct from that of the Pecten asper 

 zone. In the Wealden area the line of division appears to be less 

 clear, there has been less erosion, and the bed contains fewer fossils 

 ^ Proc. Geol. Assoc, vol. iv. p. 8. 



