ee ee ee ae ee 
Dawson and Carpenter on Eozoon Canadense. 255 
sembling those of Dr. Dawson’s Madoc specimen, represented 
in Pl, TH, figs. 4, 5), which cross the cleavage planes of the 
ll-substance in every direction. Now these parts, when 
“ng mineralogically homogeneous, and only structurally dis- 
tinguishable by the effect of their junction-surfaces on the 
Course of faint rays of light transmitted through them.— 
W.B. 0] 
EXPLANATION OF THE PLATES. 
. Plate II. 
n of Eozoon Canadense, imbedded in a dark-colored homogeneous lime- 
Stone occurring in the Lower Laurentian series in Tudor, Ontario; twO- 
of the na ize, 
Plate IT. 
Me 1 sh tion of one of the calcareous layers of the Tudor specimen (Plate 1D), 
owing canal-system imperfectly infiltrated with black (carbonaceous ?) 
show- 
—. minute form of canal-system partly injected with black matter, and 
us bodies (internal casts ?) from a specimen of Eozoon from Went- 
- Sections of a fragment of Eozoon from the Madoc limestone, showing 
120 us forms of canal-system filled with carbonate of lime; magnified 
diameters, 
