CARBONIFEROUS CONODONTS OP WEST OF SCOTLAND. 341 



Cunningham Baidland, Dairy. "^ 



Birkhead, Dairy. 



Law, Dairy. 



Low Baidland, Dairy. 



Auchenskeith, Dairy. 



Ponniel Water, near Douglas. 



Glenbuck, near Muirkirk. 



Lower 

 Limestones. 



J. S.] 



Descriptions of the Conodonts. 



Polygnathus duhius, Hinde, I.e., p. 362, pi. 16, f. 6-18. — 

 Numerous small teeth and plates are associated together in this 

 species, and some of the same form are present also in the Ayr- 

 shire deposits. The first of these has the basal portion flattened, 

 and its lower margin slightly curved; near the centre of the 

 base there is a compressed triangular large denticle, with from 4 

 to 10 similarly shaped smaller denticles on either side of it. 



I have found this form in the Devonian of America, I.e., pi. 16, 

 f. 8 j it also occurs in the Carboniferous of Ohio, I.e., pi. 57, f. 1, 

 2, 13; and of Russia, I.e., pi. 2a, f. 16. 



[In the West of Scotland it occurs at Stacklawhill, Robroyston, 

 and Birkhead. Plate IX., Fig. 1. Length, 1-3 mm. ; rare.] 



Centrodus duplicatus. Pander, I.e., pi. 2a, f. 7. — Tooth with 

 narrow, straight, elongated base, from which spring at right angles, 

 or occasionally obliquely, prominent pointed denticles, and be- 

 tween which are smaller ones. It is present in the Devonian lime- 

 stone of Canada, I.e., pi. 16, f. 12, and the Carboniferous lime- 

 stone of Tula, in Russia. [In Scotland it occurs at Monkcastle, 

 Glencart, Birkhead, and Law. Plate IX. , Fig. 12. Length of a 

 broken specimen, 1*0 mm. ; rare.] 



Centrodus lineatus. Pander, I.e., pi. 2a, f. 9. — The basal portion 

 of this tooth is narrow, elongated, straight or curved, with 

 numerous denticles arranged in a single series. Generally the 

 denticles are unequal, every third or fourth being more pro- 

 minent, and in perfect specimens a longer denticle is present near 

 one extremity of the tooth. I have figured this from the Devonian 

 of Canada, I.e., pi. 16, f. 13; and it is also present in the Car- 

 boniferous of Ohio, I.e., pi. 57, f. 4, 8 ; and of Russia. [In Scot- 

 land it occurs at Linn Spout, Glencart, Monkcastle, and Orchard. 



