20 



THE GEOLOGIST. 



the Sp. wiguicidus, Phillips, from the Devonian series, are only synonyms of the 

 present species, and to which must also be added the aS^. Goldfussiana of Prof, 

 de Koninck. It does not appear to have often exceeded about four lines in 

 length by four and a-half in width and two in depth, but is usually a much 

 smaller shell, at least so in Scotland. Sp. Urii is certauily the most abundant 

 of Scottish spirifers, and may be picked up by thousands in several localities, 

 such as at Hill Head, in Lanarkshire, where it occurs at three hundred and 

 fifty-six fathoms below the " Ell coal," and three hundred and seventy-five at 

 Kilcadzow. It is found plentifully on the east bank of the Avon, near Strath- 

 avon ; and at Coalburn, near Lesmahago. In Stuiingsliire it has been found in 

 three different stages, viz., the Craigenglen beds, under the main-limestone, and 

 in the black-limestone and shale of South Hill, Campsie. 



XVI. Spirifeea lineata. Martin. PI. xii., fig. 31. 



ConcUUolithus anomites lineatus, Martin, Petrif. Derb., tab., xxxvi., fig. 3, 

 1809 ; and Dav. Mon. Cai^b., p. 62, pi. xiii., figs. 1—13. 



In shape this shell is either transversely oval or sub-orbicular, the hinge -line 

 being much shorter than the width of the shell, and the cardinal angles 

 rounded ; the beaks are incurved and more or less approximate, the area small. 

 Ventral valve evenly convex, and rarely possessing any mesial elevation, or fold, 

 while the dorsal valve is rather deeper than the opposite one, and either 

 umfornily convex, or presenting a shallow longitudinal depression, which 

 becomes most apparent tow^ards the front. Externally the sui'face was covered 

 with numerous concentric ridges, rarely m any place more than a line apart, 

 but usually very much closer, and from each of which departed numerous con- 

 tiguous closely packed spines, which thus formed a series of rows, or fringes 

 over the shell. When the spines are absent, which is the general condition in 

 which the shell is found, the surface appears marked by numerous and regularly 

 imbricated lines, the radiating ones being produced by the small elevations from 

 which each spine took its birth, as I have attempted to show in the enlarged 

 representation, fig. 31(7, and which is very different from the irregular manner 

 in wliich the spines are scattered over the surface of Sp. Urii, of wliich fig. 30*?. 

 is an enlarged illustration. Sp. lineata is a common shell in the carboniferous 

 limestone and shales of Scotland ; but none of the examples 1 have yet seen 

 attamed the dimensions presented by some which occur both in England and 

 Ireland. 



At Gare in Lanarkshii-e Sp. lineata occurs at two hundi-ed and thirty-mne 

 fathoms lower than the " Ell coal at Braidwood, three liundi-ed and forty- 

 three ; at Harestanes, three hundi-ed and seventy-five ; and at NeMeld, foiu- 

 hundred and ten. It may also be collected at Brockley, and Middleholm near 

 Lesmahago. In Ayrsliire it occurs at Roughwood, and West Broadstone near 

 Beith ; HaUerhirst, Stevenston ; and Craigie near KHmai-nock. In Renfrew- 

 shii'e, at Barrhead ; and at Arden and Orchard quarries near Thornliebank. 

 In Dumbartoiislm-e, at Castlecary. In Stirlingshire, imder the main limestone 

 and in the Calmy limestone or Balquarhage beds, Campsie, as well as at Corrie 

 Burn. In Mid Lothian it is not rare at Drvdcn, near Edinburgh ; and at 

 Courland, near Dalkeith. Dr. Eleming mentions Dreghorn and Ayr, and it 

 was also found in Arran by Prof. Ramsay. 



Sub-genus SriRiFEKiNA. D'Orbigny. 1SI7. 

 The species located m this sub-gemis differ from Spirifera (which they re- 

 semble m external sliapc) by the perforations or canals which traverse their 

 sliells, as well as by the dovelopnicnt of a Lu-ge elevated mesial septum in the 

 interior of the vriiiral valve, to the sides of wliich was attached the adductor, 

 or oeelusor muscle. 



