PAL&ONTOLOGICAL REPORT OF GEOLOGICAL SURVEY. 575 



the periphery and sides ; septu obtusely curved backwards on the sides, 

 rapidly rising forward into conical arches on the middle of the peri- 

 phery, about three lines apart in the middle where two inches wide; 

 periphery marked in casts with an obsolete band about one line in 

 width; last chamber large, about as deep as wide; mouth subreniform ; 

 umbilicus moderately large, profound, nearly vertically walled, slight- 

 ly enlarged on the last whorl. Diameter S- T 3 -g^ inches; transverse 

 diameter of mouth about 2. 1 % 1 - 5 - inches; vertical height l. T V"o inches; 

 width of umbilicus -j\ 4 -g- of an inch. 



It is readily distinguished from iVi globatus, Sow., and iV". bilobatus, 

 Sow., with which it is related; by the size and shape of its septu, and 

 the less rapid increase of its whorls. The specimen under description 

 is destitute of spiral or transverse striae, though it is possible they may 

 exist when found in a more perfect state of preservation. 



Position and locality. Found in great abundance, converted into 

 oxide of iron and mostly imperfect; associated with G. Nolinensis, noi. 

 about one hundred feet above the conglomerate, in a stratum of ferru- 

 ginous fire-clay and carbonaceous matter; Nolin Iron Works, Edmon- 

 son county, Kentucky. Being an excellent ore it has contributed 

 largely for the manufacturing of iron. 



NAUTILUS CANALICULATUS. Cox. 

 (PI. X, fig. 3, natural size; fig. 3 a, section of a smaller specimen.) 



Discoidal, whorls two, to two and a half, increasing in width in the pro- 

 portion of . T V-o to l. T W inches; obtusely rounded on the sides; broad, 

 but shallow groove on the periphery, diminishing in depth from the 

 mouth backwards, obsolete on the first whorl when exposed, a narrow 

 indistinct band extends along the centre of the dorsal groove in well 

 preserved specimens ; septu about two lines apart in the middle, where 

 three quarters of an inch in width, curved backwards on the sides and 

 periphery, on the rounded edges of the groove they bend semi-ellipti- 

 cally forward ; umbilicus large, deep, vertically walled, exposing par- 

 tially all the whorls ; mouth transversely subovate ; diameter 2.- i % , - 5 . 

 inches; vertical height of the mouth, about l.-iW inches; transverse 

 diameter l. T Vo inches ; width of umbilicus .-£—■ of an inch. 



It differs from the N. sulcatus, Phil, by its rounded sides, greater 

 breadth on the periphery, smaller and more vertically walled umbilicus. 



Position and locality. Abundant in the same bed with G. Nolien- 



