378 THE MICROSCOPE. 



be separated into two divisions those in which the cells 

 are large, the regularity of their arrangement visible, and 

 their bond of union consisting of a single constructed por- 

 tion between each; and those in which the cells are 

 minute, not averaging more than the 900th part of an 

 inch in diameter, the regularity of their arrangement not 

 distinctly seen, and their bond of union consisting of many 

 thread-like filaments. To ascertain the mineral composi- 

 tion of the amber-coloured particles or casts, after having 

 found that it was mostly carbonate of lime with which 

 they were surrounded, they were placed for a few mo- 

 ments in the reducing flame of a blow-pipe, and it was 

 observed that on subsequently exposing them to the influ- 

 ence of a magnet, they were all attracted by it. Hence, in 

 a rough way, this rock may be said to be composed of 

 carbonate of lime and oxide of iron. 



By far the greater number of Foraminifera are marine. 

 They are found in most seas, and in those of the tropics 

 they increase both in size and variety, forming extensive 

 deposits. 



During the Canadian Geological Survey large masses 

 of what appeared to be a fossil organism, the Eozoon 

 Canadense, were discovered in rocks situated near the 

 base of the Laurentian series of North America. Dr. 

 Dawson, of Montreal, referred these remains to an animal 

 of the foraminiferal type ; and specimens were sent by 

 Sir W. Logan to Dr. Carpenter, requesting him to subject 

 them to a careful examination. As far back as 1858 Sir 

 W. Logan had suspected the existence of organic remains 

 in specimens from the Grand Calumet limestone, on the 

 Ottawa river, but a microscopic examination of one of 

 these specimens was not successful. Similar forms being 

 seen by Sir William in blocks from the Grenville bed of 

 the Laurentian limestone were in their turn tried, and 

 ultimately revealed their true structure to Dr. Dawson 

 and Dr. Sterry Hunt. 



The masses ot which these fossils consist are composed 

 of layers of serpentine alternating with calc spar. It 

 was found by these observers that the calcareous layers 

 represented the original shell ; and the siliceous layers 

 the flesh, or sarcode, of the once living creature. These 



