EOZOON CANADENSE. 379 



results were arrived at through comparison of the appear- 

 ance presented by the Eozoon with the microscopic struc- 

 ture which Dr. Carpenter had previously shown to 

 characterise certain members of the foraminifera. The 

 Eozoon not only exceeded other known foraminifera in 

 size, to an extent that might have easily led observers 

 astray, but, from its apparently very irregular mode of 

 growth, its general external form afforded no help in its 

 identification, and it was only by careful examination of 

 its minute structure that its true character could be 

 ascertained. Dr. Carpenter says : " The minute struc- 

 ture of Eozoon may be determined by the microscopic 

 examination either of thin transparent sections, or of 

 portions which have been subjected to the action of 

 dilute acids, so as to remove the calcareous shell, leaving 

 only the internal casts, or models, in silex, of the chambers 

 and other cavities, originally occupied by the substance of 

 one animal/* 



Dr. Carpenter found the preservation of minute struc- 

 ture so complete that he was able to detect " delicate 

 pseudopodial threads, wnich were put forth through pores 

 in the shell wall, of less than I0 ^ 00 th of an inch in 

 diameter " (see Plate III. figs. 64, 65) and in a paper 

 read at the meeting of the Geological Society he stated 

 that he had detected Eozoon in a specimen of ophicalcite 

 from Cesha Lipa in Bohemia, in a specimen of gneiss from 

 near Moldau, and in a specimen of serpentine limestone 

 sent to Sir C. Lyell by Dr. Giimbel, of Bavaria, all these 

 being parts of the great formation of "fundamental" 

 gneiss, which is considered by Sir Roderick Murchison 

 as the equivalent of the Laurentian rocks of Canada. 

 There can be little doubt that a rich field of research is 

 now opened to those who will undertake the examination 

 of rocks of various ages, which present the appearance 

 of analogous structure ; as it is, the microscope has been 

 the means of demonstrating the existence of animal life 

 at a very ancient geological date ; and, in the words of 

 Sir W. Logan, " we are carried back to a period so far 

 remote that the appearance of the so-called Primordial 

 Fauna may be considered a comparatively modern event." 



Eecent Foraminifera present symmetrical shells, of 



