142 Correspondence — Mr. W. Boicnes — Mr. A. Cruttwell. 



3. Where Hopkins's results on the power of water to move 

 materials ? 



4, How does Mr. Tylor arrive at a velocity of three times excess 

 of present velocity in paragraph four ? Mc Jabies. 



India. 



FOSSILS ON CLEAVAGE PLANES. 



SiK, — Until I read Mr. Carruthers' ai'ticle in the January Number 

 of the Geol. Mag. I had never realized how completely fossil 

 plant remains might be simulated by annelid trails. To me, more- 

 over, there vpas a special interest in the concluding sentence, which 

 recalled to my mind an inquiry which I had been pursuing some 

 two years ago. I was not then aware that the subject had been 

 touched upon by Dr. Sterry Hunt, nor have I seen the paper by him 

 to which Mr. Carruthers refers. I feel however disposed to call 

 attention once more to the subject as it then presented itself to me. 

 I must not reproduce remarks which have occupied more than two 

 pages, nor do I see how I can well abridge them. But 1 will ask 

 leave to refer Mr. Carruthers and the readers of his interesting 

 article to a letter by me in the September (1880) Number of your 

 Magazine, pp. 430-2. It was there pointed out that not only 

 " fucoids " (which might very probably have been annelid borings), 

 but that Graptolites also had been found upon cleavage planes. 



Kentisbbarb, Collumpton. W. Downks. 



DR. HECTOR'S "NEW ZEALAND GEOLOGY." 

 Sir, — I see in the January Number of this Magazine a notice of 

 the above Memoir, in which Dr. Hector classifies the Coal-producing 

 strata of New South Wales as Permian. There has long been a 

 dispute amongst Australian geologists as to the age of these 

 deposits, many supposing them to be Triassic, or even Oolitic, 

 presumedly upon the presence of Glossopteris ; but it would be of 

 interest to know Dr. Hector's reason for placing them amongst the 

 Permian. In the many conversations which I have had with the 

 late Rev. W. B. Clarke, F.R.S., upon the subject, he has invariably 

 upheld their true Carboniferous age, and, as a field geologist 

 who has had much experience amongst the Coal Fields of South 

 Wales, Somersetshire, and New South Wales, I certainly cannot 

 see much doubt on the subject. The Wianamatta Shales, noticeably 

 in the Parramatta District, bear a close lithographical resemblance 

 to the shales, clods, and clifts of the Gilfach-fargoed, and Mynyd- 

 dyslwyn, Upper Carboniferous deposits of Glamorgan and Mon- 

 mouthshire, and also contain obscure impressions, which certainly 

 look like Stigmarian rootlets. The Hawkesbury Sandstone, which 

 underlies the Wianamatta Shales, contains numerous cavities, 

 especially at St. Leonard's, Sydney, which look very much as if 

 they had been filled by Carpoliths, like the Trigonocarpum of the 

 Pennant of South Wales and Somersetshire, and indeed bears a 

 lithographical resemblance to that deposit. The Upper Marine Beds 

 and Upper Coal-Measures of the Newcastle (N.S.W.) and Bulli 

 Districts contain, besides Glossopteris, undoubted Sigillarian and 



