99 



numerous and more strongly marked ribs, which are alternately short 

 and long, and its umbilicus, though closed in some specimens, is open 

 enough in the majority to expose some of the iimer whorls. Nautilus 

 Neckerianus, moreover, is one of tlie characteristic fossils of the Lower 

 Greensand, whereas the rocks in which N. Suciensis occurs can scarcely 

 be older than the Gault, and are probably of a much more recent date. 



Nautilus Cajmpbelli, Meek. 



Plate 11, figures 2, 2a and 2b. 



Nautilus Campbelli Meek. — Proc. Ac. Nat. Sc, Phil., 1861, page 318. 



" " « Bui. Geol. and Geogr. Surv. of Terr., Vol. II., No. 4, p. 373, 



pi 6, figs. 2, 2a. 



Comox, Vancouver Island. Meek. Middle Shales, Division D., of the 

 North-West side of Hornby Island ; J. Eichardson, 18*72 ; and Productive 

 Coal Measures, or Division A., of the Sucia Islands; J. E., 1875. One 

 specimen from each locality. 



The position of the siphuncle of Nautilus Campbelli was unknown to 

 its describer, but the two specimens collected by Mr. Eichardson, both 

 of which are half-grown shells, shew this character with great clearness, 

 and give some additional information about the species. The siphuncle 

 is placed very near to the inner margin of the septum, its distance from 

 the periphery being four-fifths the entire height, at least, in comparatively 

 young shells. The septum figured is the largest one obtained : following 

 its concavity the entire height along the median line is ten lines, and 

 the centre of the siphuncle is eight lines from the outer and two from the 

 inner margin. The umbilicus is deep but narrow, and remains of it 

 are sometimes left as hollow, funnel-shaped, shelly cones projecting on 

 either side of the early volutions. The surface of the latter, as viewed 

 under an achromatic microscope with an inch and a-half objective, is seen 

 to be marked by shallowly concave revolving grooves, and these are 

 crossed by rather distant, transverse, crenate ridges, the intervals between 

 which are almost filled by close set, numerous crenate striae which ran 

 parallel both to each other and to the ridges. 



(Nautilus Dekayi, Morton. 



Nautilus Dekayi, Morton. — Synops. Org. Rem. Cr. Rocks of U. S., p. 33, pi. 8, fig. 4. 

 " " " Meek, Rep. Inv. Cr. and Tert. Fobs, of U. Miss. Co., p. 496, 



pi. 27, figs, la, 6, c, d, e. 



On page 124 of the first volume of the Transactions of the Academy 

 of Science of St. Louis, dated 1857, Dr. B. F. Shumard says that " a 



