Fossils Xcar Montreal. — Schiichcrt. 251 
Of the first species, there are two good ventral valves which 
agree well with small C. coiuplanata as determined by Clarke.'^ 
The Canadian specimens, however, agree best in size and form, 
with an undescribed species of the Helderbergian(Becraft lime- 
stone) of Port Jervis. New York, but differ in the far fainter 
thread-like strife which are arranged as in Rafincsqiiina alter- 
nata yet not so distinctly bundled as in Chonostrophia rcversa 
Whitfield, of the Onondaga. The Port Jervis species may be 
known as C. jerz'ciisis, and is distinguished by its size and flat- 
ness, but particularly by the equal, sharply elevated, somewhat 
undulating, and regularly disposed striae. It generally has three 
prominent, slightly diverging, cardinal spines on each side of 
the ventral beak, but there are also specimens with four spines, 
and others apparently with but the two lateral ones prominent- 
ly developed. In C. iiwnfrcalcusis, there appear to be four sim- 
ilar cardinal spines. 
Chonostropliia begins in the New Scotland zone of the 
Helderbergian in C. hcldcrbergiac, and continues upwards as 
follows: C. jcrvcnsis in the Becraft limestone, C. iiwntrcaloisis 
in the higher Helderbergian, C. coiuplanata throughout the 
Oriskany, C. coiuplanata dawsoni in the Gaspe sandstone of 
Quebec, and C. rcversa in the Ohio Onondaga (Corniferous). 
MIDDLE DEN'OXIC F.VUNA. 
It has been stated (p. 248) that in the grassy slope and 
above the Helderbergian rocks in the agglomerate of Saint 
Helen's island, there is a large block of a slightly granular 
siliceous limestone containing a few species of brachiopods 
usually preserved as natural moulds. These fossils were 
heretofore regarded as of Helderbergian age, but the species 
are different and indicate a more recent formation. The Na- 
tional Museum collection includes the following forms : 
Dalmauella planicouvcxa Hall? 
There arc three specimens of a DahnancUa present, 
which seem to be much like the Oriskanian variety of D. 
planiconvexa. These orthoids, of the group D. tcstu- 
dinaria, are difficult to distinguish unless the material is 
good, and in the present case, therefore, only the general 
aspect can be indicated. 
• Memo. N. Y. State Xlus., iii, no. 3, 1900, pi. 7, fig. 7. 
