DAVIDSON — SCOTTISH CARBONIFEROUS BRACHIOPODA. 233 



correctly figured in tlie " Geology of Yorkshire," and may ttus liave led some 

 to doubt the identity. Phillips' specimen, which may be seen in the British 

 Museum, and of which I possess a beautiful drawing, for which I am indebted 

 to my valued and distinguished friend, Mr. S. P. Woodward, consists of a shell 

 and counterpart, or rather the shell is equally divided between the two sides of 

 the split nodule, so that neither of them show the true structure. When the 

 shell is removed, the matrix shows regular concentric strise, similar to those 

 above described, but elsewhere only fractured Imes of laminae and radiating 

 striae. The nodule is black, and the shell dark and pyi'itous : it will be figured 

 in my larger work. Some Scottish examples of L. squamiformis have attained 

 thirteen lines in length by eight and a-half in width, but the generality of spe- 

 cimens are smaller, and the shell is very often found enclosed in ironstone 

 nodules. 



In Lanarkshire it occurs at Uaes Gill, at three hundred and forty-one fathoms 

 below "Ell coal;" three hundred and forty-three at Hall Craig; three hundred 

 and seventeen at Braidwood Gill ; three hundred and fifty-four at Langshaw 

 Burn ; it is found also at Hall Hill, near Lesmahago. In Renfrewshire, at 

 Orchard-quarry, Thornliebank. In Dumbartonshire, at Netherwood, near 

 Castlecary. In Stirlingshire, in the Mill Burn beds, Campsie main limestone, 

 and Corrie Burn beds. It is also found at Bishopbriggs, three miles north 

 of Glasgow. In Haddingtonshire, at Cat Craig, near Dunbar. In Edm- 

 burghshire, at Wardie (Western Breakwater, Granton) ; and occurs also in 

 Bate, Pifeshire, and the Berwickshire coast. 



XLYIL— LiNGUL.i ScoTicA. Davidson. PI. v., figs. 36-37. 



This shell is of an elongated triangular shape, tapering at the beak, slightly 

 rounded laterally and in front. The valves are slightly convex, but much com- 

 pressed, while the entire surface is covered with numerous minute concentric 

 striae, with still wider flattened interspaces. This remarkable species is easily 

 distinguished by its triangular shape and tapering sides and beaks, as well as by 

 the delicate sculpture which adorns its surface. In shape it approaches to 

 certain exceptional examples of Phillips' Lingula cuneata ; but the Carboniferous 

 and Silurian species cannot be confounded.* L. Scotica is perhaps the largest 

 Scottish Carboniferous species of the genus hitherto discovered, for several ex- 

 amples have measured fifteen lines in length by twelve and a-half in width ; and 

 a fragment in the Museum of Practical Geology would denote still larger pro- 

 portions. The interior has not been hitherto discovered ; but upon an internal 

 cast obscure Lingula-like indications of occlusor muscular impressions could be 

 perceived. 



This Lingula occurs at Gare, in Lanarkshire, at two hundred and thirty-nine 

 fathoms below the " Ell coal," and from which locality it has been known to a 

 friend in Carluke for upwards of thirty years.f My attention was, however, 

 first directed to the shell by Mr. Young, who had been struck by its peculiar 

 triangular appearance, and it was subsequently discovered at Robroyston, north 

 of Glasgow, in beds upon a similar horizon to that of Gare, while the largest 

 examples were procared by Dr. Slim on, from Hall Hill, Auchenheath, and 

 Coalburn, Lesmahago, about three hundred fathoms below " Ell coal. 



* I possess also an American Lingula from the Pottsdam sandstone of the Falls of St. Croix, 

 Minnesota, which is stated by Mr. Worthen to be the oldest known American species of the 

 genus. In shape it is very similar to L. Scotica, but differs from it in sculpture as weU as in 

 the convexity of its valves. 



t This shell has been known for many years in Scotland as a Posidonomya, but of which 

 genus it does not possess the character. ' 



YOL. III. 2 G 



