Report of the State Geologist. 237 



From the Keokuk group of Iowa and Illinois, Prof. Hall has 

 described two species, Spirifer subcusjndatus and Spirifer propinquus, 

 two varieties which I believe are referable to S. texta. Regarding one 

 of these forms. Prof. Hall* said: "So far as I can now determine 

 [/S'. textus] is identical with the one described by me as S. subcuspidatus." 

 Specimens of the latter from the typical locality were sent to the late 

 Dr. Davidson, and he regarded them, according to Mr. Meek,"}" as 

 identical with the S. cuspidata of Europe. Specimens are so labeled 

 in the Illinois State collection. I have pointed out above the con- 

 spicuous differences between 8. carteri, S. cuspidata and S. texta. 



Associated with S. subcuspidata are specimens which Prof. Hall 

 separated, because of their having " the sinus deeper, the area 

 entirely flat, and the number of plications more numerous," and at 

 that time he had "not observed intermediate forms which will justify 

 the union of this and the preceding species, though they are nearly 

 allied." To these he gave the name Spirifer propinquus. Messrs. 

 Meek and Worthen illustrated the original type used by Prof. 

 Hall, and mention having found the characteristic transverse plate and 

 a punctate shell structure. I have seen a number of typical specimens 

 of S. subcuspidata and S. propinqua from the Keokuk shales of Craw- 

 fordsville, Indiana, as well as intermediate specimens which have proven 

 to me the great variability of Syringothyris texta. This variability is 

 equally as great, if not greater among the New Providence specimens 

 of which I have had before me no less than twenty specimens. 



S. A. Miller, finding the name S. subcuspidata, Hall, preoccupied by 

 Schnur, changed it to S. cuspidatiformis, which becomes a synonym for 

 S. texta, as that species is regarded by me to be identical with the 

 last. 



Distribution. — Waverly group, Sciotoville, Ohio. Knobstone group, 

 near New Albany and New Providence, Indiana. Keokuk group, 

 Crawfordsville, Indiana; Keokuk, Iowa; Warsaw and Nauvoo, Illinois. 



Stringothtkis alta. Hall's sp. 



Spirifer alta, Hall, 1867. Pal., N. Y., vol. 4, p. 248, pi. 43, figs. 1-7. 



Casts of the ventral area of this species from Union City, Pennsyl- 

 vania, show that the long, narrow deltidium was filled for nearly 

 two-thirds of its length by the transverse plate. The deltidial opening 

 was closed by a lamellose convex covering, extending to within a 

 short distance of the dorsal valve where it left a semicircular opening. 



* Palaeontology, New York, vol. 4, p. 252. 1867. 



t Proceedings Philadelphia Academy Natural Sciences, vol. 9, p. 276, 



