lii PROCEEDINGS OF THE GEOLOGICAL SOCIETY. 



forms are, in their opinion, nothing but imbedded imitative crystal- 

 lizations, quite distinct from the foraminiferal structure with which 

 they have been compared. From these and other considerations 

 thej' conclude that Eozoonal Serpentine is a metamorphic rock, and 

 they throw out the suggestion that it may, in many cases, have 

 also undergone a pseudomorphic change — that is, it may have been 

 converted from a gneissoid calcareous diorite by chemical introduc- 

 tions or eliminations. 



Dr. Carpenter maintains the correctness of his former views. 

 In a paper read on the same evening he showed that a recent 

 siliceous cast of Amphistegina from the Australian coast exhi- 

 bited a perfect representation of the " asbestiform layer." He 

 then showed that this asbestiform layer exhibited in Eozoon a series 

 of remarkable variations, which can be closely paralleled by those 

 which are found in the course of the ''tubuli" in the shells of 

 existing Nummuline foraminifera, and are associated with a structure 

 exactly similar to the lacunar spaces intervening between the out- 

 side of the proper wall of the chambers and the intermediate skeleton 

 by which they became overgrown, formerly inferred by the author 

 to exist in Calcarina. With regard to the opinions advanced by 

 Prof. King and Dr. Eowney, he stated that even if the dendritic 

 passages hoUowed out in the calcareous layers, and the arrangement 

 of the minerals in the Eozoon limestone could be accounted for by 

 inorganic agencies, there still remained the ISTummuline structure of 

 the chamber-wall, to which no parallel can be shown in any un- 

 doubted mineral product. 



The question is certainly one of great importance, and^ considering 

 the minute microscopical structure and the mineral as well as me- 

 tamorphic change which the rocks have undergone, it is still in- 

 volved in some obscurity. It were much to be desired that the 

 gneissoid rocks from other localities should be carefully ex- 

 amined ; for if the organic theory be true in the case of old Lau- 

 rentian gneiss, we ought to expect a fuller confirmation of it in the 

 gneissic rocks of a still younger age. And though it may perhaps 

 be considered rash in one who has not examined the various speci- 

 mens microscopically beyond seeing some of Dr. Carpenter's prepara- 

 tions, I am bound to say, almost against my own convictions, that 

 the balance of argument at present is in favour of the views laid 

 down by Dr. Carpenter, Dr. Dawson, and Mr. Sterry Hunt. I should 

 add that Dr. Carpenter also stated that he had recently detected 

 Eozoon in a specimen of Ophicalcite from Bohemia, in a specimen of 

 gneiss from near Moldau, and in the serpentinous limestone from 

 Bavaria. 



With reference to this subject. Prof. A. Sismonda has published an 

 account of some organic impressions found on a mass of gneiss de- 

 rived from one of the boulders in the diluvium which overlies the Lias 

 formation north of Rezzago in the Brianza. This block must have 

 been brought down from the Alps, and Prof. Sismonda considers 

 that it probably came from the Yaltellina, the mountains of which 

 consist of tills same form of gneissic rocks. When first discovered, 



