Correspondence — Mr. A. J. Jukes Browne. 47 



lies on the Lancashire side so high on the hills close up to the water- 

 shed, and so much above the summit level of the low pass between 

 Todmorden and Rochdale, that I think erratics may very well have 

 been washed down out of the glacial beds into the Calder Yalley by 

 ordinary rain and river action. 



I am also puzzled by the statement, " You may always be sure 

 that, wherever heather and peat occur, the rock below the surface is 

 sandstone. You will never find the heather growing on a bed of 

 limestone, or shale, or clay, but always on sandstone." I have 

 myself noticed that peat is very often, not to say generally, under- 

 lain by a bed of yellowish clay, which forcibly reminded me of the 

 underclay of a coal-seam. J. R. Daktns. 



H. M. Geological Survey, Bridlingtox Quay. 



CHLORITIC MAEL AJSTD UPPER GREENSAJSTD. 



g IK; — Will you allow me to make a few observations in reply to 

 Mr. C. J. A. Meyer's " Notes respecting Chloritic Marl and Upper 

 Greensand," which appeared in the Geological Magazine for 

 December, 1878. 



Let me in the first place thank Mr. Meyer for pointing out the 

 probability that Captain Ibbetson included two distinct beds "in 

 actual contact, but widely separated in age," under the term Chloritic 

 Marl. The idea had not occurred to me, and I have not had an 

 opportunity of refreshing my recollection of the Isle of Wight 

 sections since I took up the question of the Chloritic Marl ; it would 

 seem, however, to be a very probable supposition, but assuming it 

 to be correct, I fail to see how it improves Sir. Meyer's position. On 

 the contrary, it appears in my opinion to form a still greater objec- 

 tion to the classification proposed in his paper on the Cretaceous 

 Rocks of Beer Head. 



Mr. Meyer maintains that he was correct in correlating beds 10 

 to 12 of that section with Ibbetson's Chloritic Marl. i.e. with what 

 he himself defines as embracing "the (local) top of the Upper Green- 

 sand and the (local) bottom of the Chalk Marl of the Isle of Wight." 

 Now, granting for the moment the correctness of this correlation, he 

 has surely committed himself to a classification that cannot possibly 

 be retained. If, indeed, these are the beds which were originally 

 united under the name Chloritic Marl, it becomes very clear that 

 such an application of the term cannot any longer be admitted, and 

 with it, therefore, must fall also Mr. Meyer's nomenclature. 



Whatever was the original signification of Chloritic Marl (and I 

 think the question is likely to remain rather obscure), I still believe 

 that it was the glauconitic base of the Chalk Marl only to which the 

 term was applied by most subsequent observers. Mr. Meyer must 

 excuse me for pointing out that the instance he gives to the contrary 

 hardly goes for much, since Forbes was associated with Ibbetson in 

 the original description of Chloritic Marl, and the memoir referred 

 to was written by Forbes in 1850, a year only after the publication 

 of Captain Ibbetson's Notes. It is possible, however, that the 

 Chloritic Marl of the Geological Survey Memoirs, issued in 1862, 



