S6 Reports and Proceedings. 



The rounded form of the granular masses of chondrodite, coccolite 

 etc., in some limestones was also referred by the authors to the 

 gradual removal of their surfaces by deep-seated hydrothermal 

 agency. 



It was then argued that the organic nature of Eozoon cannot be 

 supported by the cumulative evidence afforded by the combination 

 of foraminiferal features ; for these features, combined and due to 

 purely mineral paragenesis, had occurred to the authors in certain 

 ophites, though some are wanting in other ophites, just as they are 

 not always present in the Eozoonal rock of Canada. 



Serpentine has been described as having been deposited in the 

 cavities of Eozoon, and having taken the place of its sarcode ; but 

 the authors criticised all the quoted analogies of such a precipitation 

 of any siliceo-magnesian substance, disbelieved them, and put aside 

 glauconitic infiltration as beside the question. 



Considered geologically, with reference to its occurrence in a 

 metamorphic rock, the authors regarded the Eozoon as an organic 

 impossibility ; and they asked why it should never be found in any- 

 thing but crystalline or semi-crystalline rocks — in ophites or ophi- 

 calcites of widely different ages. Particularly they found Eozoonal 

 structure in the Liassic ophite of Skye ; and this they described in full. 

 They criticised Sterry Hunt's change of opinion, who used to think 

 that the serpentinous rocks of Canada were once earthy amorphous 

 silicates, and afterwards metamorphosed, but who now supposes they 

 were deposited in a crystalline state ; and they asked why, if so, 

 may not all the Laurentian rocks have been so deposited ? In con- 

 clusion, they totally denied that Eozoonal structure has anything to 

 do with any organism, and repeated that, like all analogous conditions 

 of serpentine, chondrodite, etc., it is of purely mineral origin. 



Discussion. — Prof. Ramsay had been struck long ago by the organic appearance 

 of the structure now regarded as Eozoon. He had also felt a difficulty in accounting 

 for the existence of large masses of limestone, except by the operation of organisms 

 living in the sea, in which such deposits had been formed. He could not imagine 

 the sea-water so overcharged with calcareous matter as spontaneously to deposit 

 limestone. 



Mr. Parker, on examining the various parts of the Eozoon as shown him by Dr. 

 Carpenter, had been able to recognise iu them similar structures to what he had 

 already met with in recent Foraminifera. 



Prof. T. Rupert Jones accounted for the difficulty that sometimes existed in re- 

 cognizing Eozoonal structure by the contortion of the containing beds subsequently to 

 their deposition. 



Dr. Duncan had been struck in the earlier known specimens of Eozoon by the 

 shape of the tubules of the canals : he had never seen similar outlines in inorganic 

 bodies. 



Dr. Carpenter said that he need not repeat the grounds on which he regarded this as 

 an organic structure. He objected to criticisms unless founded on examination of 

 actual specimens. Sir Wm. Logan had been first led to regard the Eozoon as organic 

 by finding alternations of calcareous and siliceous layers in various minerals. A speci- 

 men which Sir "William had brought from Canada contained much iron, and had 

 the canal system wonderfully preserved ; and it presented this character — that the 

 larger branches were infiltrated with serpentine, and the middle branches with 

 sulphide of iron, while the smallest branches were filled with carbonate of lime, of 

 the same nature as the matrix. It was only under a favourable light that these 

 smaller tubes were visible, as the calcite in them was of the same crystalline character 

 as the surrounding network. This was conclusive evidence of the structure not 



