Black Shale of Eastern Kentucky. 389 



brachiopod shell, and in view of the difficulty of getting at the 

 true generic elements of these forms, and of the paucity of even 

 specific characters, a structural peculiarity such as this should 

 be given the same weight or even more than the same weight 

 allowed in other instances. Therefore I believe that the rank 

 of Lingulipora as a subgenus of Lingula is rather under than 

 over-estimated. 



Lingula {Lingulipora) Williamsana n. sp. 



Figs. 6-6 c , p. 395. 



Lingula spatulata (pars) Yanuxem. 



Lingula sp. Hall and Clarke, 1892, Pal. New York, vol. iii, 

 pt. 1, p. 17, pi. 4', fig. 8. 



Shell small, elongate, subquadrate ; length about 1J the 

 breadth. Sides nearly straight and parallel. Posterior end in 

 the dorsal valve broadly rounded ; more acute in the ventral 

 valve. Anterior margin more or less straight, rounding gently 

 to meet the sides - . Surface ornamented with innumerable fine 

 concentric lines with occasional faint varices of growth. The 

 fine concentric striae under a rather high magnifier (they can be 

 only just distinguished with an ordinary hand lens) are seen to 

 be rather wavy, but much less so than some other ornamented 

 Lingulas (e. g. L. melie) and on the whole are comparatively 

 simple and direct. 



Shell substance strongly punctate and, for the size of the 

 shell, rather coarsely so. 



Length of a large individual 7 mm , width 4 mm , usually a trifle 

 smaller than these measurements. 



Locality and position. In the Devonian black shale at Berea, 

 Ky.; near Vanceburg, Ky.; near Jefferson, Montgomery Co., 

 Ky.; near Indian Fields, Clark Co., Ky.; White Creek Springs, 

 Davidson Co., Tenn., and also in the Styliola layer of the 

 Genesee shale at Bristol, Ontario Co., New York, where it is 

 associated with Lingula spatulata ; also from the same horizon 

 at Seneca Lake, IS". Y. 



This species is evidently the same form figured by Hall and 

 Clarke in the citation mentioned above, where attention is called 

 to its punctate structure. The punctae can often be seen as 

 fine papillae on the outside of the shell, among and interrupting 

 the striae, especially toward the front. 



These authors cite L. Williamsana from near Yanceburg r 

 Ky., and I have found it abundant in the black shale of Ken- 

 tucky and Tennessee. Comparatively few Lingulas from the 

 same general horizon in New York have passed through my 

 hands, but there also it proved proportionally so plentiful that 

 suspicions were aroused that this might after all be the real 



Am. Jour. Sci. —Fourth Series, Vol. VI, No. 35. — November, 1898. 

 27 



