C. J. A. Meyer — Chloritic Marl and U])per Greensand. 547 



instance, as the exact age of the Aberystwyth group and the origin of the beach 

 pebbles— will be clearly made out. As the work progresses, I hope to publish 

 elsewhere more detailed accounts, and to describe the fossUs. But the imperfection 

 is the greater on account of the necessity which obliges me to write these pages 

 when absent from Wales and without materials at hand to help me. 



III. — Notes respecting Chlokitic Marl and Upper Greensand. 

 By C. J. A. Meyer, F.G.S. 



HAVING paid but little attention to geological literature during 

 the last two years, it was not until September, 1878, that I 

 became aware of Mr. A. J. Jukes Browne's article in the Geological 

 Magazine of August, 1877.' In this article, amongst other matters, 

 the author criticises very fairly the classification of the Upper 

 Greensand and "Chloritic Marl," so-called, as set forth in my paper 

 on the Cretaceous Eocks of Beer Head.^ In justice to certain 

 questions involved, I find myself compelled to reply to this criticism, 

 and to say a few words besides respecting the Chloritic Marl and 

 Upper Greensand. 



In my description of the Cretaceous Eocks of Beer Head — after 

 showing the great difference between the faunas of the highest and 

 lowest beds of what had been always previously classified as Upper 

 Greensand, and after proving that the one represented a Blackdown, 

 the other a Warminster fauna — I suggested that beds 10 to 12 of my 

 section therein given, on account of their special fauna, should be 

 separated from the Upper Greensand under the distinctive title of 

 Warminster Beds. I further pointed out that beds 10 to 12 re- 

 presented, both in fauna and position, the so-called " Chloritic Marl" 

 of the Isle of Wight. 



In suggesting the term Warminster Beds for my beds 10 to 12, 

 I ought at the time, indeed, to have explained that by such term 

 I meant that portion only of the Warminster strata from which, at 

 Chute Farm, near Warminster, so rich a fauna has been collected, 

 and which fauna has been always spoken of, erroneously as I think, 

 as coming from the Upper Greensand of Warminster. For the 

 actual " Upper Greensand " of Warminster, as every one knows, 

 is of considerable thickness. It consists in the lower part of sandy 

 marl, resting at Crockerton on Gault, and passing upwards, as in the 

 coast sections, into sands with Chert ; — the usual " Malm Series " 

 and " Chert Series," in fact, of the Upper Greensand. 



But none of these beds contain the noted " Warminster fossils." 

 These fossils are, and always have been, collected from the surface 

 of the field in which they once abounded, the rock which yields, or 

 yielded, them being unexposed. Portions of the matrix may be seen, 

 however, both outside and inside many of these fossils, and such 

 matrix has the appearance of Chloritic Marl, although the cement is 

 now siliceous instead of calcareous. 



The " Chute Farm " fauna is then the Warminster fauna, as 

 generally known. It is also the fauna, in great measure, of my beds 



1 Geol. Mag Dec. II. Vol. IV. p. 350. 

 - Quart. Journ. Geol. Soc. vol. xxx. p. 369. 



