164 Mr. De la Beche on the Geology 



These limestones occur in beds from a few inches to several feet in thick- 

 ness; the usual colour is grey, varying in intensity; they are frequently 

 traversed by calcareous veins, and, in texture, vary from compact to semi-cry- 

 stalline, the latter predominating- in the vicinity of trap, and when the strata 

 are much disturbed. The semi-crystalline limestones afford a great variety 

 of beautifully tinted marbles, not so well known, nor so much employed for 

 ornamental purposes as they deserve to be. 



These limestones are, here and there, interstratified with shale : they also 

 rest upon a considerable thickness of argillaceous shale, into which they seem 

 to pass. The shale is usually reddish in the upper part, brownish grey in the 

 lower and larger portion, and strongly reminded me of the shale similarly 

 situated in Pembrokeshire. 



The most abundant organic remains are encrinites and corals. The lime- 

 stones at Daddy's Hole near Torquay, are so full of pieces of encrinites, as to 

 resemble, in this respect, the Black Rock of Bristol. The following- is a list 

 of the organic remains which I met with in this rock, including those found 

 at Bradley quarries near Newton Bushel : 



Corals. 



Encrinites. 



Trilobites. 



A very singular fossil*, specimens of which were collected in the vicinity 

 of St. Mary Church. The sections which have been made of these specimens 

 exhibit no internal structure which enables me to refer them to any known 

 class of organic bodies. 



Cardium alajforme Min. Con. T. 552. f. 2. 



Megalodon cucullatus Sow. Gen. & Sp. Nov. Min. Con. T. 568. 



Terebratula porrecta Sow. Sp. Nov. 



Ibid with 5 or 6 small plaits in front. 



Ibid with 8 or 10 ditto. 



y, .1 J J Trigonal, depressed, with four large plaits on the elevated 



\ front, and as many on each side. 



Spirifer decurrens Sp. Nov. 



rotundatus ? Min. Con. T. 461. f. 1. 



Ibid. Sp. Nov. 



* Plate XX. figs. 1. & 2 It is not improbable that the fossil here referred to may have 



belonged to the Tunicata. The structure of the external covering appears to have some resem- 

 blance to that of Chelyusoyiia MacLeayaniimy a new genus and species of that group, brought 

 home by Lieut. Belcher, R.N. presented by him to the Zoological Society, and described and 

 figured in the Zoological Journal, vol. v. p. 46. Tab. III. figs. 4. 5. & 6. ; but, in none of the 

 specimens of C. MacLeuyamim examined by the writer of this note, does the number of plates, 

 which are coriaceous and confined to the upper surface, exceed eight. — W.J.B. 



