Trenton Gasteropoda of Manitoba. 321 
One of the most abundant species of gasteropoda in the 
Trenton limestone of Manitoba is a large Murehisonia which 
the present writer has identified with the WM. major of Hall, 
but which does not seem to differ materially from M. belli- 
cincta exceptin size. Specimens of this Murchisonia (which 
had previously been collected at two localities on the 
Nelson River in Keewatin by Dr. R. Bell in 1879), were 
obtained by Mr. Weston, in 1884, at Hast Selkirk and Lower 
Fort Garry, at Elk, Big and Deer Islands, Big Grindstone 
Point, the Dog’s Head, and Jack Fish Bay, Lake Winnipeg > 
by Mr. Tyrrell in 1889 at Berens (or Swampy) Island; and 
by Messrs. Dowling & Lambe in 1890 at Black Bear, Snake, 
Little Tamarack and Jack Head islands, in Lake Winnipeg. 
All the specimens from these localities, like those of MM. 
major from Wisconsin, are mere casts of the interior of the 
shell, which are imperfect at both ends but especially so at 
the larger end. They rarely exceed four inches and a half 
in length and not more than six volutions are preserved. 
Not a vestige of the surface ornamentation can be detected 
on any of them, and indeed Professor Whitfield has ex- 
pressed the opinion that the fossils from the States of New 
York and ‘Wisconsin, which have been described as M. belli- 
cincta and M. major,avé not true Murchisonias, as, so far as 
he has observed, ‘none of them show any evidence of 
having been marked with a revolving band.” In regard to 
the typical form of M. bellicincta it may be remarked that 
Ferdinand Roemer has figured a Kuropean specimen of it, 
in which the spiral slit-band, and backwardly divergent 
growth lines are clearly shown on each of the volutions, on 
Plate v, fig. 7, of the Atlas to the first volume of the . 
Lethxa Geognostica, published in 1876. 
In 1890 Messrs. Dowling & Lambe collected, at Berens 
Island, Lake Winnipeg, two specimens which throw quite a, 
new light on this point and upon the characters and affini- 
ties of this large variety of I. bellicincta. One of these is 
upwards of seven inches and the other fully eight inches in 
length, and nine volutions can be counted in each. The 
shorter of the two has the test preserved on the last two 
