102 THE MICROSCOPE AND ITS REVELATIONS. 



Canada, which has its parallel in Europe in the * fundamental gneiss ' of 

 Bohemia and Bavaria, and in the very earliest stratified rocks of Scandi- 

 navia and Scotland. These beds are found in many parts to contain 

 masses of considerable size, but usually of indeterminate form, disposed 

 after the manner of an ancient Coral Reef, and consisting of alternating 

 layers frequently numbering from 50 to 100 of Carbonate of Lime and 

 Serpentine (silicate 'of magnesia). The regularity of this alternation, 

 and the fact that it presents itself also between other Calcareous and 

 Siliceous minerals, having led to a suspicion that it had its origin in 

 Organic structure, thin sections of well-preserved specimens were sub- 

 mitted to microscopic examination by Dr. Dawson of Montreal, who at 

 once recognized its Foraminiferal nature: 1 the calcareous layers present- 

 ing the characteristic appearances of true shell, so disposed as to form an 

 irregularly chambered structure, and frequently traversed by systems of 

 ramifying canals corresponding to those of Calcarina ( 484); whilst the 

 serpentinous or other siliceous layers were regarded by him as having 

 been formed by the infiltration of silicates in solution into the cavities 

 originally occupied by the sarcode-body of the animal, a process of 

 whose occurrence at various Geological periods, and also at the present 

 time, abundant evidence has already been adduced. Having himself 

 taken up the investigation (at the instance of Sir William Logan), the 

 Author was not only able to confirm Dr. Dawson's conclusions, but to- 

 adduce new and important evidence in support of them. 3 Although 

 this determination has been called in question, on the ground that some 

 resemblance to the supposed organic structure of Eozoon is presented by 

 bodies of purely Mineral origin, 3 yet, as it has been accepted not only by 

 most of those whose knowledge of Foraminiferal structure gives weight 

 to their judgment (among whom the late Prof. Max Schulze may be 

 specially named), but also by Geologists who have specially studied the 

 Micro-mineralogical structure of the older Metamorphic rocks, 4 the 

 Author feels justified in here describing Eozoon as he believes it to have 

 existed when it originally extended itself as an animal growth over vast 

 areas of the sea-bottom in the Laurentian epoch. 



1 This recognition was due, as Dr. Dawson has explicitly stated in his original 

 Memoir (" Quarterly Journal of the Geological Society," Vol. xxi., p. 54), to 

 his acquaintance not merely with the Author's previous researches on the mi- 

 nute structure of the Foraminifera, but with the special characters presented by 

 thin sections of Calcarina which had been transmitted to him by the Author, 

 Dr. D. has given an excellent account of the Geological and Mineralogical rela- 

 tions of Eozoon, as well of its Organic structure, in a small book entitled " The 

 Dawn of Life." 



2 For a fuller account of the results of the Author's own study of Eozodn, and 

 of the basis on which the above reconstruction is founded, see his Papers, in 

 " Quart. Journ. of Geol. Soc.," Vol. xxi., p. 59, and Vol. xxii., p. 219, and in the 

 " Intellectual Observer," Vol. vii. (1865), p. 278; and his ' Further Researches,' in 

 "Ann. of Nat. Hist.," June, 1874. 



3 See the Memoirs of Profs. King and Rowney, in " Quart. Journ. of GeoL 

 Soc.," Vol. xxii., p. 185; and " Ann. of Nat. Hist.," May, 1874. 



4 Among these the Author is permitted to mention Prof. Geikie, of Edinburgh, 

 who has thus studied the older rocks of Scotland, and Prof. Bonney, of Cam- 

 bridge and London, who has made a like study of the Cornish and other Serpen- 

 tines. By both these eminent authorities he is assured that they have met with 

 no purely Mineral structure in the least resembling Eozoon, either in its regular 

 alternation of Calcareous and Serpentinous lamellae, or in the dendritic exten- 

 sions of the latter into the former; and while they accept as entirely satisfactory 

 the doctrine of its Organic origin maintained by the Author, they find them- 

 selves unable to conceive of any Inorganic agency by which such a structure 

 could have been produced. 



