BRACHIOPODS. 81 



Horizon and localities.ljower Carboniferous, Burlington 

 limestone: Hannibal. 



The specimen figured under this name, though slightly 

 smaller than Swallow's type, is believed to represent this 

 species. 



Spirifera logani HALL. 



Spirifer logani Hall, 1858: Geology Iowa, vol. I, p. 647, pi. xxi, tigs. 



la-b, and 2. 

 Fpirifer Icevigatus Swallow, 1863 : Trans. St. Louis Acad. Sci., vol. II, p. 



86. 



Shell very large, with close analogies to S. grimesi, but 

 having a much longer hinge-line, coarser plications and much 

 thicker test. 



Horizon and localities. Lower Carboniferous, Keokuk 

 limestone: Wayland and St. Francisville (Clark county); 

 Keokuk (Iowa). 



Spirifera Icevigata of Swallow is too poorly described to 

 deserve recognition. Moreover, it seems probable that Swal- 

 low had in hand a water-worn valve of 8. logani, not uncommon 

 at Keokuk and elsewhere. 



Spirifera kelloggi SWALLOW. 

 Spirifer kelloggi Swallow, 1863 : Trans. St. Louis Acad. Sci , vol II, p. 86. 



A small plicated form closely resembling 8. spinosus of 

 Norwood & Pratten, but apparently having no spines. 



Horizon and localities Lower Carboniferous, Keokuk 

 limestone : Keokuk ( Iowa ). 



Spirifera keokuk HALL. 



Plate xl, fig. 2. 



Spirifer keokuk Hall, 1858: Geology Iowa, vol. I, p. 642, pi. xx, figs, 



3a-d. 



Spirifer littoni Swallow, 1860 : Trans. St. Louis Acad. Sci., vol. I, p. 6 46. 

 Spirifer keokuk var. shelbyensis Swallow, 1866 : Trans. St. Louis Acad. Sci., 



vol. II, p. 410. 



Shell rather small, robust, transversely elliptical. Plica- 

 tions coarse, rounded; mesial fold and sinus well defined. 



Horizon and localities Lower Carboniferous, Keokuk 

 limestone : \Vayland ( Clark county ) ; Keokuk ( Iowa ). 

 G 7 



