548 C. J. A. Meyer — Chloritic Marl and Upper Greensand. 



10 to 12 of Beer Head, and of the so-called " Chloritic Marl " of 

 the Isle of Wight, and of Chardstock. Was I wix)ng then in 

 suggesting the separation of beds 10 to 12 from the Upper Greensand 

 and applying to them the term " Warminster Beds " ? ' 



Dr. C. Barrois, Mr. A. J. Jukes Browne,^ and probably many 

 other geologists, consider that I was wrong. Because, say tlaey, the 

 fauna of beds 10 to 12 is found also in the Upper Greensand. But 

 where? Not at Beer Head. And, with the exception of Pecten 

 asper and one or two other wide-ranging fossils, not at Warminster. 

 Nor yet, in reality, in the Isle of Wight. Barrois, quoting from 

 older lists, gives indeed a number of species as coming from the 

 Chert Beds at Warminster,^ and others as from the Upper Greensand 

 of the Isle of Wight.* The greater part of these however came, 

 probably, on his own showing, from the base of the " Chloritic 

 Marl " of Ibbetson. To prove this I also, following Mr. Jukes 

 Browne's example, must say a word or two respecting that much- 

 abused term, " Chloritic Marl." 



Now Mr. Jukes Browne,^ in his otherwise careful and valuable 

 resume on the origin and application of the term " Chloritic Marl," 

 has failed, apparently, to notice one point of considerable importance 

 in respect to it, and one from which in fact has arisen very much of 

 the difference in thought and practice regarding the application of 

 the term. And it is this : — That under the term " Chloritic Marl," 

 Captain Ibbetson (in 1849) would seem to have included two beds of 

 very similar composition ; both loaded with green grains, both 

 phosphatic. Beds which although in actual contact were certainly 

 in age widely separated. Captain Ibbetson's "Chloritic Marl" 

 embraced in fact the (local) top of the Upper Greensand, and the 

 (local) bottom of the Chalk Marl of the Isle of Wight. 



For " The Chloritic Marl," says Captain Ibbetson,^ " divides the 

 Chalk Marl from the Upper Greensand. It is a grey marl full of 

 green grains of a silicate of iron and sand, very fossiliferous. The 

 upper part in places exhibits a conglomerate of pebbles and small 

 boulders, and in it the fossils are chiefly broken as if rolled on a 

 beach." 



Now, all who have examined the junction-beds of the Upper 

 Greensand and Chalk Marl near St. Catharine's Down, in the Isle 

 of Wight, will see the significance of the above description. The 

 " conglomerate of pebbles and small boulders " occurs on the actual 

 line of division of two faunas. The lower of which includes Pecten 

 asper, Terebratella pectita, Catopygus coliimbarius, Galerites castanea 

 and various other Echinoderms ; the upper, Ammonites, Scapliites, 

 Turrilites, etc., mostly phosphatic. It might, perhaps, be objected that 



1 Quart. Journ. Geol. Soc. vol. xxx. p. 371. 



2 Geol. Mag. Dec. II. Vol. IV. p. 358. 



3 Kecherches sur la Terrain Cre'tace sup. de I'Angleterre, par Ch. Barrois, D.Sc, 

 Lille, 1876, p. 58. 



* L'Age des Couches de Blactdown, par. Ch. Barrois, D.Sc, An. Soc. Geol. du 

 Nord, torn. iii. p 4. 



s Geol. Mag. Dec. II. Vol. IV. p. 355. 



6 Notes, etc., on the Strata of the Isle of Wight, London, 1849. 



