AMERICAN GEOLOGY THE EOZOON QUESTION. 



639 



The chemical and mineralogical side of the problem was taken up 

 b}^ T. Sterry Hunt, who found that the silicate portion, i. e., the 

 material filling the chambers, was composed of serpentine or pyroxene 

 in some of its forms. 



It is not surprising that the finding of supposed fossil remains in 

 rocks so old as those of the Laurentian should have excited the widest 

 attention, and it would have been strange indeed had such conclusions 

 been allowed to go unchallenged. In 1866 a there was read before the 

 same society a detailed account of the investigations made by Profs. 

 William King and T. H. Rowney, of Queen's University in Ireland. 

 These gentlemen, although claiming to have had no misgivings at the 

 commencement of their investigations as to 



the Eozoonal origin of the material, never- / ; I '-, '< ..' J {'/ > 



theless attacked the problem from the phys- 

 ical and chemical rather than the biological 

 standpoint. The}' examined in great detail 

 all of the structures described by Dawson, 

 though not having access to all his materials. 

 Their conclusions were to the effect that (1) 

 the so-called chamber casts or granules of 

 serpentine were more or less simulated by 

 minerals like chondrodite, coccolite, pargas- 

 ite,etc. ; (2) that the i% intermediate skeleton'' 

 was closely represented both in chemical 

 composition and other conditions by the 

 matrix of these minerals; (3) that the proper 

 wall of Dawson was structurally identical 

 with an asbestic-form la} T er which w T as fre- 

 quently found investing the grains of chon- 

 drodite, and that instead of belonging to the 

 skeleton it was altogether independent of 

 that part and formed an integral portion of 

 the serpentine constituting a chamber cast; 

 (4) that the canal system was analogous to 



the embedded crystallizations of native silver and other similarly con- 

 ditioned minerals; and (5) that the type examples of casts of stolon 

 passages were isolated crystals apparently of pyrosclerite. From these 

 considerations and the perhaps even more important one that the 

 Eozoonal structure was found only in metamorphic rocks and never in 

 unaltered sedimentary deposits, they concluded that every one of the 

 specialties which had been diagnosed for the Eozoon <■</,<,/</, ns< was of 

 purely crystalline origin. 



Such conclusions naturally brought forth prompt rejoinders from 

 Carpenter and others, the controversy becoming in some cases per- 



FlG. 128.— Magnified and restored 

 section of a portion of Eozoon 

 canadense. The shaded portions 

 show the animal matter of the 

 chambers, tubuli, canals, and 

 pseudopodia; the unshaded por- 

 tions the calcareous skeleton. 

 (AfterJ. W. Dawson.) 



a Quarterly Journal of the Geological Society of London, XXII, 1866, p. 185. 



