[marrnew] ORDOVICIAN SYSTEM ON THE ATLANTIC COAST 267 
“var. RETROFLEXA, de Verneuil, PI. II. figs. la-c. 
Gonambonites retroflexa, Pander, Beitr. zur geogn. Russl., p. 77, pl. 25, figs. 1 & 2, 
“ This variety figured by Mr. Pander under the name of Gonambonites 
retroflexa is recognized by the extreme height of the dorsal [ventral] area. 
by the minuteness on the contrary of the ventral [dorsal] area, reduced 
to the degree that it is not more than the fifth of the first, by its cardinal 
angle more pointed, and finally by the length of the shell. The greatest 
width is not at the cardinal border, but beyond the middle of the shell. 
and the dorsal [ventral ?] valve is much more tumid than the ventral 
[dorsal ?]. All these differences are softened by insensible transitions. 
The same modification of the ventral area, which is so striking in this 
variety, is not there constant, and exists sometimes, on the contrary, in 
the type species. Without particular attention this variety might be 
taken for a distinct species.” 
The variety found at Cape Breton would agree with retroflexa rather 
than the type, but for the remark as to the relative tumidity of the 
valves ; this excludes it unless there has been a transposition of the 
terms dorsal and ventral in this part of the description. 
Certain features of the dorsal valve not described by de Verneuil are 
the following : 
A mould of the dorsal valve shows that there was a median groove 
running from the umbo, nearly two-thirds of the length of the shell : 
and on each side of the groove appear three radiating vascular ridges 
(furrows of the interior surface ?). At the hinge line are the moulds of 
two short lateral plates, and at the centre of this line a group of three 
pits due to the crure and the cardinal process ; this, the central pit, which 
is due to the cardinal process, is larger than the others. 
Size.—Length of the ventral valve 16 mm. Width 20 mm. 
Locality—Gray sandstones of McFee’s Point, near George River, 
Cape Breton, in company with Lingulella Selwyni, collected by Messrs. 
Weston and Robert. 
HYOLITHES, Eichwald. 
HYOLITHES cf. TENUISTRIATCS, Linrs., Pl. 11. figs. Za and b. 
A large species of this genus occurs in company with Lingulella 
Selwyni in the gray sandstones of McFee’s Point, which is nearly reiated 
to the above Swedish species. It also resembles the Bohemian /. 
maximus, Barr., and the American H. princeps, Bill., but appears to be a 
later species than any of these. 
Apical angle about 12°. No grooves were observed within the 
margins on the dorsal side and no furrow at the median line on the 
ventral side. This side somewhat flattened on the sides but much more 
