Ee views — Dawsoiis Dawn of Life. 169 



ized Foraminifer, or merely an arrangement of mineral substances 

 more or less resembling foraminiferal structure, it appears that, as is 

 natural, some observers, mineralogically inclined, lay great stress on 

 the mineral ogical analogies, similarities, and composition; while 

 others, recognizing what they believe to be the inimitable, but 

 petrified, structure of a Foraminifer, regard it as an organism. 

 Further, the former think they know enough of Foraminiferse to be 

 able to deny that there is as much of the special structure as they 

 are told is there ; and, on the other hand, the foraminiferists, if 

 geologists too, think they know enough of minerals to be able to 

 weigh fairly any doubts in that direction. How like other discus- 

 sions polemic, whether in politics or theology ! 



There are exceptions also to this grouping of the disputants ; 

 for not only do many professed mineralogists hesitate to claim 

 Eozoon as wholly inorganic ; but, on the contrary, at least one ex- 

 pert in Ehizopoda, as seen in his papers in the '' Annals of Natural 

 History," does not recognize a perfect representation of the Fora- 

 minifer in Eozoon. 



In 1852, 1858, 1863, and subsequently, the late Sir W. Logan and 

 his colleagues of the Geological Survey of Canada discovered in the 

 Laurentian Serpentine-marble of the Grand Calumet, on the Ottawa, 

 at Grenville and elsewhere (Petite Nation, Burgess, Tudor, and 

 Madoc), specimens of a fossil form, externally like Stromatopora Midi 

 Stromatocerium, but internally consisting of somewhat irregular 

 layers of calcite and magnesian silicates, and, under Principal Daw- 

 son's and Dr. W. B. Carpenter's microscopes, showing an arrange- 

 ment of constituent parts analogous to what is only found in the 

 shell-tissue of some Foraminifera, such as Calcarina, Nummulina, and 

 their allies, the cavities of the shell being occupied by the silicates, 

 rarely by dolomite and even calcite, and still more rarely remaining 

 empty. Sir W. Logan and Dr. Dawson defined the fossil as an organism 

 consisting of a foraminiferal shell, or calcareous tubuliferous test, once 

 inclosing numerous segments of sarcode (now replaced by silicates'), 

 spreading out laterally and piled up vertically, as large sessile 

 patches, about a square foot in extent, 5 or 6 inches thick, and con- 

 taining microscopic tubes and tubules, mostly filled with loganite, 

 etc. Accumulations of these cake-like patches make up large portions 

 of the green and white marbles referred to, and have partaken of 

 the mechanical and chemical disturbances and alterations which the 

 limestone bands and the inclosing gneiss have undergone. Obscure 

 traces of perhaps crinoidal fragments in the limestone, and the 

 presence of graphite, apatite, and iron ore are regarded as indicative 

 of the existence of organisms in the Laurentian seas ; worm-tubes 

 occur in associated rocks ; and pebble-beds in the gneiss prove the 

 every-day water-action which produced the now metamorphosed beds. 

 The heaping-up of broken serpentinous and calcitic Eozoon, over and 

 beyond the recognizable patches, was pointed out by Sir W. Logan 



^ White pyroxene, pale grey serpentine, loganite (a dark green aliimino-magnesian 

 silicate, allied to chlorite and pyrosclerite in composition, but differing in structure), 

 pyrallolite and rensselorite. 



