184 



THE GEOLOGIST. 



diating from two nuclei on either side of an elevated medial line. The 

 stone in which they are embedded is unquestionably the Stonesfield 

 slate ; it contains the characteristic Trigonia angulata, Rhynchonella, 

 Ostrea, and Modiola Soiverbi/ana, D'Orb. ( = plicata, Sowerbv). The 

 enigmatical bodies to which I now allude are stained of a deep red- 

 ferruginous colour, the matrix retaining the grey tint and crystalline 

 texture of the Stonesfield slate. On comparison between these re- 

 mains and those of the specimens of Geomyda spinosa, from Singapore, 

 in the British Museum, presented by Sir A. Smith, a comparison which 

 was suggested to me by Mr. Davies, whose accurate discrimination 

 first threw light upon the nature of the present evidence, 1 have been 

 led to consider that the specimens in the Fossil Gallery represent the 

 second, third, and fourth median scutes of a tortoise allied to the recent 

 African species. The fossils and their corresponding impressions 

 from the Stonesfield slate afford, according to my interpretation, 

 evidence of the texture of the horny scutes which were developed 

 outside the bony carapace of the old Oolitic tortoise. A particular 

 interest is attached to these specimens, as they were considered by 

 the late Edward Forbes as Trigonellites, or opercula of Ammonites. 



Since the above was written, I learn that Dr. J. E. Gray, several 

 years ago, considered the present evidences to be Chelonian. I am 

 indebted to my friend Mr. S. P. Woodward, F.G.S., for this infor- 

 mation, and am now aware that the true signification and interpreta- 

 tion of these remains has been known to him for a long period. 



Dear Sir,' — My notice of the Dura Den Glyptolepis, in your number 

 for March last, M as merely intended to correct an impression which Mr. 

 Mitchell's paper in your February number seemed calculated to convey, 

 namely, that it was he who first pointed out the propriety of transferring 

 Eoloptychius Flemingi from the genus Holoptychius to Glyptolepis. In 

 doing so I seem to have expressed myself so loosely as to make it appear 

 that I claimed for myself and others the merit of first noticing the crescent 

 of points on the scales of that fish. This I by no means intended to do, 

 as I was well aware that these had been long before observed ; indeed a 

 glance at the figure given by Agassiz in his ' Vieux Gres Rouge,' pi. 22, 

 fig. 1, will show that this peculiarity had not been overlooked by him. I 

 was also aware that Professor Pander had expressed his belief that the 

 scales of Eoloptychius Flemingi and Glyptolepis leptopterus were the same; 

 these I consider specifically distinct. But lest I might seem to claim too 

 much, I forwarded to you a note to be added to my letter, which seems to 

 have arrived too late for insertion, and which, by some strange mistake, 

 has been printed in your number for this month (April) as the first para- 

 graph of a communication from the Rev. W. S. Symonds. I may add that 

 Mr. Page, of Edinburgh, was the first to point out, in my hearing, the ex- 

 istence of Glyptolepis scales in the Dura Den Sandstones. 



CORRESPONDENCE. 



