■226 PROCEEDINGS OF THE ACADEMY OF [1888. 



Sijnocladia virgulacea Geinitz, 1866. Carb. und Dyas in Nebraska, 

 p. 70. 



The only bryozoan remains from tbe black shales consist of a few 

 well preserved specimens of this species. From the investigations of 

 Meek and Ethridge it would appear that Front's genus Setopora is 

 synonymous with Synocladia, and according to the former writer 

 S. cestriensis from the Chester limestone is very closely allied to, if 

 not identical with, S. biserialis. This would give Synocladia biserialis 

 a much more extensive vertical range than has hitherto been sup- 

 posed. 



BRACHIOFODA. 



Xingula umbonata Cox. 



Lingula umbonata Cox, 1857. Geol. Surv. Ky., Vol. Ill, p. 576, 

 pi. X, fig. 4. 



Lingula umbonata "White, 1884. 13 Ann. rep. Geol. Ind., pt. II, 

 p. 120, pi. XXV, fig. 14. 



The specimens from Des Moines are somewhat larger than the 

 one originally figured by Cox {loc. cit.), and like that are broader 

 posteriorly to the mid-length than anteriorly. The posterior mar- 

 gin is broadly rounded instead of being obtusely angular as it is 

 often said to be, and as is shown in some figures of this species. 

 None of the specimens under consideration are, therefore, so promi- 

 nently subangular on the posterior margin, and broader anteriorly 

 to the mid-length as those shown in the figures of Meek and Worthen^ 

 of a form which they call L. mytiloides Sowerby, while specimens of 

 Sowerby's species figured by Ethridge^ have the posteripr margin 

 even more sharply rounded or obtusely angular. No opportunity 

 has been offered for directly comparing the American with the 

 European forms and consequently their exact specific relations have 

 not been sufficiently considered. 



Biscina nitida Phillips. 



Orbicula nitida Fhillips, 1836. Geol. Yorks., II, p. 221, pi. xi, 



figs. 10-13. 

 Discina nitida Meek and Worthen, 1873. Geol. Ill, Vol. V, p. 



572, pi. XXV, fig. 1. 

 This species is common at the Folk county coal mine but has not 

 as yet been discovered elsewhere in the county. The specimens 



1 Geol. Illinois, Vol. V, p. xxv, figs. 2a, 2b, 2c, 



« Proc. Nat. His. Soc. Glasgow, Vol. IV, pi. v, fig. 3. 



