GASTEROPOD FAUNA IN THE MILLSTONE GRIT OF SCOTLAND. 347 



Exterior. — The surface is almost smooth, but under the lens close, fine concentric 

 lines of growth, with here and there a stronger line, the latter being more conspicuous 

 in the umbonal region. The periostracum apparently thick. 



Dimensions. — Specimen No. T2743 B measures : antero-posteriorly, 5 mm. ; dorso- 

 ventrally, 5 mm. 



Locality. — In black micaceous shale in drain in bottom of Greenfoot Quarry, near 

 Gain Farm, 3 miles N. of Coatbridge. (Position of Castlecary Limestone.) 



Observations. — Two small pieces of black shale labelled T2742 B and T2743 B are 

 covered with black shiny shells and fragments which are new to me. The shells are 

 probably somewhat crushed, but they have the general shape and contour of Anthra- 

 comya, to which genus I am led to refer them. They differ from A. valenciensis in 

 being more triangular and less globular, and in having a well-marked oblique rounded 

 ridge and a very rapidly expanded posterior extremity. The comparatively thick 

 periostracum is a fact in favour of affinity of this small shell to Anthracomya. One 

 slab shows four fairly well-preserved specimens of left valves, the other a practically 

 perfect specimen of the right valve. 



For its size this species is more rapidly expanded posteriorly than any of its genus, 

 and foreshadows the character of the large Anthracomya Adamsii and its variety 

 A. Adamsii, var. expansa, of the middle portion of the Coal Measures of England. A 

 slab labelled T2156 B , from a dark shale on top of a 2-inch coal resting on the Glenboig 

 Fireclay Seam, Fireclay Mine, Glenboig. 



Edmondia excentrica, sp. nov. (PI. II. figs. 31, 32.) 



Specific Characters. — Shell small, only moderately gibbose, subrotundate, quadrate, 

 moderately transverse, inequilateral. The anterior end is bluntly rounded, the inferior 

 margin broadly convex, the posterior blunt, convex, somewhat broader than the anterior. 

 The hinge line arcuate. The umbones are small, incurved, placed in front of the 

 middle portion of the valve. 



Exterior. — The surface is ornamented with concentric lines and rugae of growth, 

 and are arranged somewhat obliquely to the long axis of the valve. 



Dimensions. — PI. II. fig. 32. Specimen No. Tl945 B measures: antero-posteriorly, 

 18 mm. ; dorso-ventrally, 12 mm. 



Localities. — Stirlingshire, Torwood Glen, 2|- miles N.W. of Larbert, 9 feet above 

 Castlecary Limestone ; river Avon, \ mile S.E. of Inveravon, Linlithgowshire ; Glen- 

 cryan, If miles S.S.E. of Cumbernauld, Dumbartonshire. 



Obse7'vatio?is. — A typical Edmondia, with an affinity to E. senilis, but of quite a 

 different habit of growth, hence its creation into a species. 



The Edmondia reflexa of Meek, from the Coal Measures of North America, is a 

 more transverse shell with more regular and less rugose markings. 



TKANS. ROY. SOC. EDIN., VOL. XLVI. PART II. (NO. 15). 53 



