STRUCTURES OF OPHITES AND RELATED ROCKS. 11 



" chambers." Such layers of serpentine are admitted to graduate 

 into the plates, lenticuloids, and spheroids above mentioned, and 

 thus to constitute the " acervuline variety of Eozoon." 



Interlamellations of the kind are not confined to the Archaeans 

 of Canada, as they, with other eozoonal features, have been 

 made known by us to be present in the post-Archcean green 

 marbles of Connemara and the Jurassic ophite of the Isle of Skye*. 

 They have been observed by one of us in a hydrous dolomite in 

 contact with an igneous rock near Predazzo ; and he was shown 

 by Prof. Miiller a specimen in the museum at Basle, from Kalk- 

 gebirg, Todte Alps, Davos, in the Engadine. A similar rock, we 

 suspect, occurs somewhere in Southern Italy; for the fragments 

 of coarse verd antique lying amongst the ruins of Pompeii and 

 Herculaneum consist of rude alternations of calcite and serpen- 

 tine ; and the " marble " columns, perforated by pholases, still 

 standing erect in the ruined temple of Serapis, at Puzzuoli, have 

 been formed out of a rock apparently of the same kind. 



The serpentinyte of the Lizard, Cornwall, has afforded us a 

 great variety of bodies, consisting of serpentine, saponite, and 

 other mineral silicates, and resembling corals, foraminifers, 

 worm-tubes, as will be seen in our paper published in the 

 ' Philosophical Magazine/ ser. 5, vol. i. pi. 2. Other simulations 

 of organisms have lately occurred to us in the same rock : one, 

 a plate (apparently of feldspar undergoing a change), is riddled 

 in the most regular manner, so as to have the closest resem- 

 blance to a leaflet of Retepora cellulosa. 



A number of silacid ophites (ophi-euphotides &c.) have quite a 

 porphyritic structure a common occurrence in those of Central 

 Italy. We have, in the paper just referred to, shown that the 

 serpentinyte of the Lizard is porphyritic, containing crushed 

 crystals, originally of augite, but now possessing the cleavage and 

 lustre of chlorite f. 



* Proc. Roy. Irish Acad. new ser. vol. i. (January, 1871). 



t Since this paper was published, the Rev. Prof. Bonney and Mr. W. 

 Hudlestone have noticed these crystals, in the l Quarterly Journal of the 

 Geological Society/ vol. xxxiii., the former stating that they are altered 

 enstatite (pp. 921, 922), and the latter that " their chemical composition is 

 similar to that of bastite j and they are probably the result of the hydration 

 of a variety of enstatite " (p. 926). The latter statement may be taken as 

 confirmatory of our earlier idea that the crystals are pseudomorphs of chlorite 

 after augite. 



