On the Microscopic Structure of the Eozoon- Serpentine. 159 



January 10, 1866. — W. J. Hamilton, Esq., President, in the Chair. 

 The following communications were read : — 



1. " On the Origin and Microscopic Structure of the so-called 

 Eozoon -Serpentine." By Prof. W. King and Dr. T. H. Rowney. 



Taking the Grenville Rock as its type, "Eozoonal Serpentine" 

 was defined by the authors to consist essentially of variously formed 

 granules of Chrysotile, or some other allied mineral, imbedded in, 

 or intermixed with, Calcite. Although differing from the type in 

 some respects, the varieties of Serpentine which they have examined 

 from Connemara, Donegal, the Isle of Skye, India, Bavaria, and the 

 State of Delaware are considered to belong to the same section. 

 The Serpentine from Cornwall, the Isle of Anglesea, and Saxony, 

 which appears to be devoid of " Eozoonal" structure, they were dis- 

 posed to look upon, but with considerable doubt, as an eruptive 

 rock. The authors stated their conviction that every one of the 

 presumed organic structures of "Eozoonal" Serpentine is purely 

 and primarily mineral or crystalline. The " skeleton" they held to 

 be identical with the calcareous matrix of certain minerals, notably 

 Chondrodite, Pargasite, &c. They adduced various considerations 

 and evidence to show that the " proper wall " cannot have resulted 

 from pseudopodial tubulation ; and, instead of being an independent 

 structure, in their opinion it is no more than the surface-portion of 

 the granules of Chrysotile crystallized into an asbestiform layer. 

 The dendritic and other forms, considered to represent the " canal 

 system," were shown to be tufts of Metaxite, or some other allied 

 variety of Chrysotile ; while the resemblance they bear to some 

 which are common in crystalline limestones, also their identity to 

 the imbedded crystallizations of native silver, moss agates, &c, 

 and the total dissimilarity between them and the foraminiferal struc- 

 tures with which they have been homologued, are points which the 

 authors held to be conclusively fatal to the view which contends for 

 such forms being of organic origin ; in their opinion they are no 

 more than imbedded " imitative" crystallizations. What have been 

 taken for " Stolons," they were convinced are for the most part 

 crystals of Pyrosclerite. The " chamber-casts " were considered to 

 be identically represented among both minerals and rocks, — in the 

 former by the grains of Chondrodite, Pyrallolite, Pargasite, &c. ; 

 and in the latter by the segmented kernels of native copper, Zeo- 

 lites, &c, in eruptive rocks; also by the remarkable botryoidal and 

 other shapes which occur in the Permian limestone of Durham. The 

 authors concluded by offering it as their opinion that "Eozoonal" 

 Serpentine is a metamorphic rock ; and they threw out the sugges- 

 tion that it may in many cases have also undergone a pseudo- 

 morphic change ; that is, it may have been converted from a gneis- 

 soid calcareous Diorite by chemical introductions or eliminations. 



2. " Supplemental Notes on the Structure and Affinities of Eozoon 

 Canadense." By W. B. Carpenter, M.D., F.R.S., F.G.S. 



In this paper Dr. Carpenter stated that a recent siliceous cast of 

 Amphistegina from the Australian coast exhibited a perfect repre- 

 sentation of the " asbestiform layer " which the author described in 



