WHAT IS EOZOON 



91 



known should be determinable by tlie comparison of a portion 

 which the smallest pin's head would cover, with organisms at 

 present existing." 



(C.) :N'ote on Specimens from Long Lake and Wentworth. 

 [Journal of Geological Society, August, 1867.] 



'' Specimens from Long Lake, in the collection of the Geo- 

 logical Survey of Canada, exhibit white crystalline limestone 

 with light green compact or septariiform* serpentine, and 

 much resemble some of the serpentine limestones of Grenville. 

 Under the microscope the calcareous matter presents a deli- 

 cate areolated appearance, without lamination ; but it is not an 

 example of acervuline Eozoon, but rather of fragments of such 

 a structure, confusedly aggregated together, and having the 

 interstices and cell-cavities filled with serpentine. I have not 

 found in any of these fragments a canal system similar to that 

 of Eozoon Canadense, though there are casts of large stolons, 

 and, under a high power, the calcareous matter shows in many 

 places the peculiar granular or cellular appearance which is 

 one of the characters of the supplemental skeleton of that 

 species. In a few places a tubulated cell-wall is preserved, 

 wich structure similar to that of Eozoon Canadense. 



" Specimens of Laurentian limestone from Wentworth, in the 

 collection of the Geological Survey, exhibit many rounded sili- 

 eious bodies, some of which are apparently grains of sand, or small 

 pebbles ; but others, especially when freed from the calcareous 

 matter by a dilute acid, appear as rounded bodies, with rough 

 surfaces, either separate or aggregated in lines or groups, and 

 having minute vermicular processes projecting from their sur- 

 faces. At first sight these suggest the idea of spicules ; but I 

 think it on the whole more likely that they are casts of cavities 

 and tubes belonging to some calcareous Foraminiferal organ- 

 ism which has disappeared. Similar bodies, found in the 

 limestone of Bavaria, have been described by Giimbel, who 

 interprets them in the same way. They may also be com- 



* I use the term " septariiform " to denote the curdled appearance 

 so often presented by the Laureutian serpentine. 



