GONIOPHORA. 
17 
narrow and convex. Antero -inferior margin very long, undulating in two gentle 
convex and concave curves to the produced inferior point. Posterior margin 
long, straight, oblique. Postero-inferior margin oblique (?). Contour of shell in 
front of the keel obliquely flat, and behind the keel obliquely concave. Lunule 
very small and deep, cordate, defined. Hinge-line bearing one if not two small 
oblique teeth on each valve below the umbo, and, perhaps, a long, transverse, 
lateral tooth behind. Surface in front of the keel marked with very numerous, 
straight, erect, sharp, foliaceous, transverse, divaricating ridges or threads, and 
behind it apparently only with a few growth-lines. Shell-structure very thin. 
8ize. — The only specimen I know is too imperfect for measurement. It 
seems to have been a considerably larger shell than Phillips's, whose figure 
measures 74 mm. in greatest length. 
Locality. — A single specimen from Wolborough is in the Museum of Practical 
Geology. 
BemarJcs. — This specimen consists of the superior half of a left valve, and in 
the above description I have used Phillips's figure to supply as far as possible 
characters which are not seen in it. Phillips's type I have been unable to find, 
but there is not the slightest doubt that it belonged to the same species, as it 
corresponds with it in every particular. It is quite dissimilar from any other 
fossil from these localities. The Museum specimen is not in a very good state of 
preservation, and the hinge-line shows signs of having been considerably weathered. 
The general shape of its teeth is, however, clear. There is a small, narrow, 
oblique tooth under the umbo in front of a narrow groove, and preceded by 
another small, deep, triangular groove, which in turn is preceded by another 
small tooth. The shell appears to have been very deep, and of a peculiar shape, 
being produced obliquely backwards from a rather short straight hinge-line to a 
sharp inferior corner, and not being simply elongate, as would be imagined from 
the position of Phillips's figure. 
Phillips is undoubtedly wrong in identifying it with Megalodon carinatus, 
Goldfuss. Its external shape is distinctly diflFerent, and its hinge is totally 
unlike, and proves at once that it has no affinity with that shell. 
Goniophora gallica, (Ehlert,^ has a longer hinge-line, and appears to be a 
more evenly rounded shell. 
All the species of Goniophora described by Hall differ in having very much 
longer hinge-margins, except G. truncata, Hall,^ which is radiated and more arched 
anteriorly, and G. Glaucus, Hall,^ which is more oblique and has a longer hinge- 
margin and a differently shaped hinge. 
1 1888, ' Bull. Soc. Geol. Fr.,' ser. 3, vol. xvi, p. 657, pi. xv, fig. 5. 
2 1885, Hall, ' Pal. N. T.,' vol. v, pt. 1, sect. 2, p. 298, pi. xlii, figs. 9, 10 ; and pi. xliv, figs. 1—5. 
3 1885, Hall, ' Pal. N. Y.' vol. v, pfc. 1, sect. 2, p. 299, pi. xliii, fig. 16 ; and pi. xliv, figs. 10—17. 
VOL. II. 3 
