﻿A. J. Jukes Browne — On the Uppo- Greemand, etc. 351 



Harapsliire and the Isle of Wight, and it was said to assume dif- 

 ferent facies in other districts ; thus the Blackdown Beds, the War- 

 minster Greensand, and the Cambridge "Coprolite Bed," have all 

 been referred to the Upper Greensand, and have been considered as 

 local developments of that formation. It is true the two latter have 

 also more recently been called Chloritic Marl, but this only shows 

 the uncertainty attending the use of that term, and the general 

 opinion has been that they were all " Upper Greensand " ; the great 

 differences between the above-mentioned deposits being accounted for 

 by the relative distances from contemporaneous land and other vary- 

 ing geographical conditions.' 



It was known that these Greensands contained very different 

 fossil faunas, but no one had followed up the beds possessing any 

 of these local faunas, nor had the fossils even from the separate 

 beds of one locality been collected with the view of ascertaining 

 whether the succession of strata contained the same fauna from top 

 to bottom. Such investigations must inevitably have led to more 

 accurate views, but the valuable evidence afforded by the fossils was 

 to a great extent ignored, and the more obvious differences were 

 explained away in the manner above mentioned ; explanations 

 which in themselves suggest very interesting questions, but which 

 are inadequate to account for all the circumstances of the case,^ 



Within the last few years, however, the Cretaceous system has 

 been more carefully studied both in England and France, and the 

 Greensands have received their due share of attention ; the strati- 

 graphical details of the several divisions have been investigated by 

 men who were at the same time careful to pay attention to the 

 paleeontological evidence, and it is now possible to answer most of 

 the questions above indicated as obscure or unknown. 



The result of these inquiries has been to alter very materially our 

 conception of the importance of the Upper Greensand and Chloritic 

 Marl, and to render it very doubtful whether they should continue 

 to rank as divisions of primary importance in the Cretaceous series. 



It is perhaps the position of the Chloritic Marl which is at present 

 the most doubtful and undefined. Mr. C. J. Meyer has claimed for 

 it an importance equal to that of the Upper Greensand, while Mr. 

 Whitaker has expressed himself as objecting to the term altogether 

 on the ground of its being nowhere satisfactorily defined, but applied 

 in one place to Upper Greensand and in another to Chalk. 



Again, in the March Number of the Geological Magazine, p. 123, 

 the reviewer of Mr. Bonney's " Cambridgeshire Geology " takes 

 exception to the application of the term Chloritic Marl to the 

 ■Cambridge Greensand, and in the April Number, p. 191, Mr. H. G. 

 Fordham expresses surprise at this, and wishes to learn what may 

 be taken to constitute " the true typical Chloritic Marl." 



It seems therefore that it would be useful to give some general 

 account of all the Glauconitio, or mis-called Chloritic, sands between 



1 These arguments have been recently renewed by Mr. Seeley, but without the 

 support of any additional observations, and in the face of the facts brought forward 

 by Dr. Barrois and myself. 



