122 THE CANADIAN NATURALIST. [April 



transverse to the plane of contact of the two minerals ; yet they 

 are seen to traverse both the pyroxene and the serpentine with- 

 out any interruption or change. Some sections exhibit these two 

 minerals filling adjacent cells, or even portions of the same cell, a 

 clear line of division being visible between them. In the specimens 

 from Grenville, on the other hand, it would seem as if the develop- 

 ment of the Eoznon (considerable masses of which were replaced 

 by pyroxene) had been interrupted, and that a second growth of 

 the animal, which was replaced by serpentine, had taken place 

 upon the older masses, filling up their interstices. 



The results of the chemical examination of these fossils from 

 different localities may now be given: — 



I. A specimen of Eozobn from the Calumet, remarkable for the 

 regularity of its laminated arrangement, gave to warm acetic acid 

 27-0 per cent of soluble matter, consisting of carbonate of lime 

 97-1, carbonate of magnesia 2-9 ; ■=. 100. 



II. Another specimen of the fossil, from Grenville, replaced 

 by pyroxene, yielded in the same way 12*0 per cent of soluble 

 matter, which, was composed of carbonate of lime 98*7, carbonate 

 of magnesia 1*3 ; — 100. 



III. In this specimen of the fossil, which adjoined the last, 

 serpentine was the replacing mineral. The soluble portion froin 

 this equalled 47*0 per cent, and consisted of carbonate of lime 

 96*0, carbonate of magnesia 4-0 ; == 100. It thus appears that the 

 septa in these specimens of Eozoon are nearly pure carbonate of 

 lime, The somewhat larger proportion of magnesia from the last 

 is due to the use, as a solvent, of dilute nitric acidj which slightly 

 attacked the serpentine. 



The pyroxene of the above specimens is a very pure silicate of 

 lime and magnesia; that from I gave, by analysis, silica 54-90, 

 lime 27-67, magnesia 16 76, volatile matter 0-80 ; = 100-13. A 

 partial analysis of the pyroxene from II yielded lime 28-3, magnesia 

 13-8. This specimen was interpenetrated with serpentine, amount- 

 ing to about 10-0 per cent, which was first removed by the suc- 

 cessive action of heated sulphuric acid and dilute soda-ley. The 

 serpentine from III yielded silica 42*85, magnesia 41-68, protoxide 

 of iron 0.67, water 13-89; =99-09. As already mentioned, this 

 serpentine had lost a little magnesia from the action of nitric acid. 

 A similar serpentine from the Calumet, associated with the Eozoon, 

 gave silica 41*20, magnesia 43*52, protoxide of iron 0.80, water 



