1866.] KING AND EOWNEr — " EOZOONAL EOCK." 203 



We feel ourselves next called upon to show that the " amorphous 

 masses " are purely of mineral or inorganic origin. 



The Canadian examples of these bodies are remarkably uniform in 

 possessing no more than a rude divisional structure and a starch- 

 like dullness; but occasionally they present a diiferent appearance. 

 Referring agaia to figure 17, the specimen which it represents has a 

 somewhat rhomboidal shape, a well-defined prismatic structure, and 

 an incipient lustre : its prisms are for the most part parallel and 

 closely adherent to one another ; but at the sides they separate, 

 diverge, or curve outwardly, thus approximating to the scopiform 

 and sheaf^like ^' definite shapes"*. 



In these compact specimens the divisional structure is so essentially 

 mineral, such as may be seen in tremolite, kyanite, wollastonite, 

 scapolite, &c., as to prevent any mineralogist believing otherwise 

 than that it is in no respect related to anything organic : and the 

 belief is powerfully supported by the fact that specimens approxi- 

 mately similar, both in form and structure, are common, as men- 

 tioned before, imbedded in some of the primary calcareous marbles 

 of Connemara and Donegal ; nay, it may be regarded as demonstrated 

 by the occurrence of similar prismatic specimens which we find lying 

 adjacent to grains of chondrodite in saccharoidal calcite. 



The " definite shapes " are essentially Canadian, since rarely are 

 they detected in Ophite from other places. Por a long time our de- 

 calcifications of Connemara specimens of this rock yielded no more 

 than a few imperfectly formed rod-like and caulescent bodies, which 

 differ mainly from the simplest of the Canadian forms in having a 

 more crystalline appearance. We have been rewarded, however, 

 just before finishing this paper, by the discovery in Ophite from 

 Glanochan and Lisoughter of perfectly genuine examples — complex 

 ramose and dendritic forms, with more or less cylindrical stems and 

 branches — ^which occur crowding the decalcified passages. Both in 

 appearance, and circumstances of occurrence, they cannot be "dis- 

 tinguished from ordinary examples in Grenville Ophite f ; and they 

 closely resemble those figured by Dawson $, Carpenter §, and Eupert 

 Jones II . 



Nothing of the kind has yet occurred to us in any varieties of 

 Ophite we have examined from the Isle of Skye, India, Donegal, 



quainted with it ; but possibly its bearing has been misunderstood, as certainly 

 is Dr. Sterry Hunt's opinion (thus stated by Dr. Carpenter), " that the siliceous 

 infiltration of the cavities of the Eozoon was the result of changes occurring 

 before the decomposition of the animal." (See Proc. Eoy. Soc. London, vol. xiii. 

 p. 546.) 



* Another specimen before us approaches still nearer to the sheaf-like forms 

 by having all the prisms, which are somewhat apart, ranged in two divergent 

 series. 



t Whatever doubts may have hitherto existed in the mind of some as to the 

 Connemara Ophite being "eozoonal," the existence therein of the "definite 

 shapes " and the " proper wall " completely identifies it with that from GrenviUe. 



\ Quart. Journ. Geol. Soc. vol. xxi. pi. vii. fig. 4. 



§ Ibid. pi. viii. fig. 5 b, c. 



\ Popular Science Eeview, vol. iv. pi. xv. figs. 6 and 7. 



q2 



