Logan.] The Invertebrates, Benton Group. 475 



site side, but in some cases one, and sometimes each division, 

 terminates between two of the nodes on the other side. 

 Siphonal lobe somewhat longer than wide, with a moderately 

 narrow body, provided with three branches on each side, the 

 upper pair of which are small and nearly simple, while the 

 next pair are longer and each bifid, and the terminal pair, 

 which are larger than the second, are each ornamented by 

 three small, pointed branchlets or digitations, or sharp, 

 nearly or quite simple branchlets. The first lateral sinus 

 scarcely equaling in width the siphonal lobe, but longer and 

 divided at the extremity into two nearly equal branches. 

 The first lateral lobe is irregularly tripartite ; the lateral divi- 

 sions being bifid and sharply digitate, while the terminal, which 

 is not quite central, is longer than the others and has about 

 five pointed digitations or short, simple branchlets. Second 

 lateral lobe (ventral?) moderately small and obscurely bifid. 

 Second lateral sinus small, nearly as long as wide, and regu- 

 larly tripartite. Length, sixty mm. ; height, forty-eight mm. ; 

 greatest convexity, measuring from the extremities of the nodes 

 on either side, thirty-six mm." 



This species occurs in the Septaria horizon of the Blue Hills 

 shales. It occurs not only free in the shale, but also in the 

 calcareous nodules. 



Scaphites warrenii M. & H. Plate civ, figs. 5-7. 



Scnphites warrenii M. & H., 1860, Proc. Acad. Nat. Sci., Phil., p. 185; White, 

 1876, U. S. Geog. and Geol. Surv. West 100th Mer., vol. iv, p. 299, pi. xix, 

 f. 3a; Meek, 1876, U. S. Geol. Surv. Terr., vol. ix, p. 420, pi. vi, f. 5; White- 

 field, 1880, Geol. Black Hills of Dakota, p. 144, pi. xm, f. 141; Stanton, 

 1892, Bull. U. S. Geol. Surv. No. 106, p. 185, pi. xliv, ff. 4-7. 



Description: "Shell medium sized, subovate, compressed; 

 inner volutions nearly circular, closely involute, and composing 

 a comparatively rather large part of the bulk ; deflected body 

 portion short and rather more compressed proportionally than 

 the inner turns ; surface costate and without proper nodes ; 

 costse small on the inner volutions, where they do not differ 

 materially in size, but on the body part about every fourth or 

 fifth one becomes more prominent than the others, and extends 



