WHAT IS EOZOON 



91 



mown should be determinable by the comparison of a portion 

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

 >resent existinsr." 



).) Note on Specimens from Long Lake and Went worth. 



[Journal of Geological Society, August, 1867.] 



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



[ogical Survey of Canada, exhibit white crystalline limestone 



rith light green compact or septariiform* serpentine, and 



mch resemble some of the serpentine limestones of Grenville, 



Fnder the microscope the calcareous matter presents a deli- 



iteareolated appearance, without lamination ; but it is not an 



example of acervuline Eozoon, but rather of fragments of such 



structure, confusedly aggregated together, and having the 



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



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



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



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



)laces the peculiar granular or cellular appearance which is 



)ne of the characters of the supplemental skeleton of that 



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



dch structure similar to that of Eozoon Canadense. 



Specimens of Laurentian limestone from Wentworth, in the 



)llection of the Geological Survey, exhibit many rounded sili- 



bious bodies, some of which areapparently grains of sand, or small 



jbbles ; but others, especially when freed from the calcareous 



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



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



iving minute vermicular processes projecting from their sur- 



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



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



id tubes belonging to some calcareous Foraminiferal organ- 



Jm which has disappeared. Similar bodies, found in the 



lestone of Bavaria, have been described by Giimbel, who 



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



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

 often presented by the Laurentian serpentine. 



