J. W. Dawson on fossils from the Laurentian of Canada, 369 
and in the case of creatures so variable as the Foraminifera, it 
would be rash to decide whether the differences above noticed are 
of specific value, or depend on age, variability, or state of pres- 
ervation. For this reason I refer the specimen for the present to 
Hoxon Canadense, merely distinguishing it as the Tudor variety. 
From the state of preservation of the fossil, there are no erys- 
talline structures present which can mislead any ordinarily skil- 
microscopist, except the minute veins of calcareous spar tray- 
ersing the septa, and the cleavage-planes which have been devel- 
_ Oped in some portions of the latter. 
_ I would remark that, as it seemed desirable not to injure any 
_ More than was absolutely necessary a unique and very valuable 
Specimen, my observations of the microscopic structure have 
been made on a few slices of small size,—and that, as the mic- 
Toscopie structures are nearly the same in kind with those of 
specimens figured in former papers, I have not thought it neces- 
Sary to prepare numerous drawings of them; while the admira- 
ble photograph executed for Sir W. E. Logan by Mr. Norman 
ustrates sufficiently the general form and arrangement of parts. 
¢. Concluding Remarks.—In a letter to Dr. Carpenter, quoted 
ie 
bled me to make that statement were obtained at Madoc, near 
Tudor, this region being one in which the Laurentian rocks of 
Canada appear to be less highly metamorphosed than is usual. 
€ specimens from Madoc, however, were mere ste, 
e 
{ Madoc before the discovery of the fine specimen now under con- 
| Sideration, 
suarterly J My 
will hereafter still more largely il 
- Specimens 
g Lake and Wentworth—Specimens 
Lake, in the collection o 
f the Geological Survey of 
