NATURAL SCIENCES OP PHILADELPHIA. 189 



Tertiary system of the old world. One of these, F. rarisulcatus of Dcshays, (Coq. 

 Fos. p. 556, pi. T6, figs. 32, 34,) resembles it very closely in form aud surface 

 characters, but differs in having the outer lip distinctly crenulated within. 



The specific name is given in honor of Col. A. J. Vaughan, Indian Agent for 

 the Upper Missouri country, to wliose patronage we are indebted for many of 

 the Nebraska species heretofore described by us. 



Locality and position. Near mouth of Heart lliver, junction of Upper Cretaceous 

 and Tertiary beds. 



FUSUS SUBTDRRITDS. 



Shell fusiform ; spire conical, turreted, very acute at the apex : volutions 

 about seven and a half, obliquely flattened or a little concave above, conve.x, 

 and ornamented round the middle by a single row of rather prominent nodes, 

 which on the upper whorls are prolonged so as to form more or less distinct 

 vertical folds, last one tapering rather obliquely into the straight canal ; surface 

 ornamented by fine lines of growth, which are crossed by small rather regular 

 elevated thread-like lines, about equalling the spaces between ; suture linear, 

 and when viewed from above is seen to deviate from a regular curve in follow- 

 ing the undulating outline of the prolonged nodes : aperture obovate, narrowing 

 below into the canal. Length about l-TS inches ; breadth -90 inch ; apical angle 

 nearly regular, divergence 55''. 



Tbis species is more nearly related to out F. Newberryi (Proceed. Acad. Nat. Sc. 

 Philada. vol. 8, p. 66) than any shell we have seen, but differs in having a 

 more elevated spire, which is much more acute at the apex ; it also has from two 

 to two and a half more volutions than F. Newberryi, and much more i^rominent 

 nodes. 



Locality and position. Upj)er part of No. 4, near Grand River. 



FCSUS INTERTEXTUS. 



Shell fusiform, or elongate rhomboidal, rather thick ; spire conical, mode- 

 rately'' elevated ; volutions about six, convex below, sloping very obliquely, and 

 concave above, ornamented round the middle by a regular row of vertically elon- 

 gated nodes ; last whoi'l tapering rather gradually into the canal ; suture not very 

 distinct ; surface ornamented by well marked lines of growth, which are crossed 

 by strong, elevated, revolving lines, less than the spaces between on the middle 

 and upper portions of the whorls, but smaller, more crowded, and sometimes 

 alternating in size, below the middle of the last turn ; aperture narrow obovate, 

 obtusely angular above, narrowing gradually below ; margin of outer lip sharj) 

 or bevelled, prominent in the middle, retreating above and below ; inner liji 

 scarcely distinct from the slightly arcuate columella. Length about 1-87 inches : 

 breadth -86 inch: apical angle convex, divergence 50°. 



In many respects this species approaches our F. Newberryi (Proceed. Acad. 

 Nat. Sc. Philada. vol. 8, p. 66,) but differs in the greater elevation of its spire, 

 more elongated form, and stronger, as well as more distant revolving lines. It 

 also has about one more volution, and the apical angle measures 5° less. 



Like Fusus Newberryi, in the prominence of the middle of the outer lip, and 

 consequent subsinuate character of its upper part, this shell approaches some 

 varieties of Pleurotoma, but appears to be a true Fusus. 



Locality and position. Yellow Stone River, 150 miles above its mouth, in a 

 bed apparently a blending of No. 4 and 5 of our section. 



Fusus (Pleurotoma ?) Scakboroughi. 

 Sliell fusiform ; spire conical, acute at the apex ; volutions about six and a 

 half, flattened, or slightly concave above ; .last one contracting abruptly below 

 into a small (rather short?) canal ; suture small, not deeply impressed ; surface 

 ornamented by fine regular lines of growth, crossed by numerous distinct, rather 

 closely arranged, elevated, thread-like lines, which are slightly variable in size, 

 but generally equalling the spaces between ; sometimes more closely crowded 

 and smaller just below the suture, than on the middle of the whorls ; aperture 

 narrow ovate, angular above, tapering into the canal below ; outer lip thin, 



1857.] 



