278 



beds. Forms apparently identical to these occur in the lower Chazy of 

 New York. 



OrhUjnyella nodosa, new species, is very abundant in the Lebanon lime- 

 stone near Big Spring, Tennessee. 



Oi-bignyclla suMameUosa Ulrich and Bassler, was first described from the 

 Pierce beds near Murfreesboro, Tennessee, but further stratigraphic study 

 of the Stones River group has shown that it is much more abundant and 

 widely distributed in the Ridley limestone than any other species in that 

 formation. 



RANGE AND DISTRIBUTION OF OTHER SPECIES OF THE STONES 

 RIVER GROUP IN CENTRAL TENNESSEE. 



The table (page 310) is given to express briefly the relation of the 

 Mollusca, ostracode sponge and coral faunas from the Central Basin region 

 with the faimas of Stones River age from other localities and those of 

 younger age found in Tennessee and elsewhere. 



DESCRIPTONS OF GENERA AND SPECIES 

 ORDER CYCLOSTOMATA BUSK. 



The arangement of the zooecia, the form of the zoarium, and the presence 

 or absence of interstitial cells and vesicular tissue are the important char- 

 acters upon which the families and genera of this order is founded. 



The zooecia are simple and short, with minutely porous calcareous walls. 

 Diaphragms are absent. The apertures are rounded, slightly raised, bent 

 outward, and inoperculate. Ovicells are present. 



Family Ceramoporidae Ulrich. 



Members of this family may be identified by the more or less oblique 

 aperture with an elevated lunarium often developed into a hood. The cell 

 walls are minutely porous and composed of irregularly laminated and inti- 

 mately connected tissue. Maculae of mesopores or of zooecia longer than the 

 average occur at regular intervals. Diaphragms are few ; mesopores are 

 generally present, irregular and free from tabulation. 



Genus Ceramoporclla Ulrich. Genotype : Ceramoporella distincta Ulrich. 

 Ceramoporella Ulrich. Jour. Cincinnati Soc. Nat. Hist., 5, 1882, p. l.")(i. 

 Miller, N. A. Pal., 1889, p. 297. Ulrich. Geol. Surv. Illinois, 8, 1890. pp. 380, 

 464; Geol. Minnesota, 3. 1893, p. 328. Procta, Syst. Sil. Centre Boheme, 8, 

 pt. 1, 1894, p. 1.5. Ulrich, Zittel's Textb. Pal. (Engl, ed.), 1896, p. 267. 

 Simpson, 14th Ann. Rep. State Geol. New York for 1894, 1897, p. 564. 

 Nickles and Bassler, Bull. U. S. Geol. Surv., 173, 1900, p. 23. Bassler, ibid., 

 292, 1906, p. 20. Grabau and Shimer, N. A. Index Fossils, 1, 1907, p. 121. 

 Cunnings, 32d Rep. Dep. Geol. Nat. Res. Indiana, 1908, p. 742. Bassler, Bull. 

 U. S. Nat. Mus., 77, 1911, p. 81 ; Zittel-Eastman Textb. Pal., 1913, p. 327. 



Zoarium consists of incrustations often superposed, forming masses, zo- 

 oecial tubes are short and thin-walled, with apertures that are more or less 



