On Specimens of Eozoon Canadense. 223 
which I have called Middle Laurentian, especially in the 
district east of the Ottawa, vindicate the results of the late 
Sir William Logan as to the continuity of the great lime- 
stones, their regular interstratification with the gneisses, 
quartzose gneisses, quartzites, and micaceous schists, and 
their association with bedded deposits of magnetite and 
graphite, and also the regularity and distinctly stratified 
character of all these rocks. Farther, I regard the Upper 
Laurentian, independently of the great masses of Labradorite 
rock, which may be intrusive, as an important aqueous 
formation, characterised by peculiar rocks, more especially 
the anorthite gneisses. I am also of opinion that some of 
the crystalline rocks of the country west of Lake Superior 
are stratigraphically, and to a great extent lithologically, 
equivalent to the Upper Laurentian of St. Jerome and other 
places in the Province of Quebec, differing chiefly in the 
greater or less abundance of intrusive igneous rocks. 
(10.) Imitative Forms. 
The extraordinary mistakes made by some lithologists in 
studying imperfect examples of Kozoon and rocks supposed 
to resemble it, and which have gained a large amount of 
currency, have rendered necessary the collection and study 
of a variety of laminated rocks, and considerable collections 
of these have been made for the Peter Redpath Museum. 
They include banded varieties of dolerite and diorite, of 
gneiss, of apatite and of tourmaline with quartz, laminated 
limestone with serpentine, graphic granites, and a variety 
of other laminated and banded materials, which only 
require comparison with the genuine specimens to show 
their distinctness, but many of which have nevertheless 
been collected as specimens of Kozoon. I do not propose to 
enter into any detailed description of these here, but may 
hope, with the aid of Dr. Harrington, to notice them in 
forthcoming Memoirs of Peter Redpath Museum. 
It is easy for inexperienced observers to mistake lamin- 
ated concretions and laminated rocks either for Stromatopora 
