96 On the Transition Hochs of the Cataraqui. 



cidedly a transition formation," the more particularly as our chief aim 

 and object is not to found new and presumptuous theories, but to de- 

 velope facts in accordance with the received notions of the geologists 

 of the present day. 



The inference we have drawn, that this limestone is decidedly a 

 transition rock, of the elder class, is formed on the following circum- 

 stances, which have been collected not hastily, but as the results of 

 long and mature reflection and observations made under favorable op- 

 portunities. 



In addition to what we have already stated concerning this lime- 

 stone, it is subcrystalline, the nature of this property being rendered 

 discernible chiefly by the glimmering lustre of the points and facets 

 of calcareous spar reflecting light, and it is traversed by small contem- 

 poraneous veins of that mineral. Its grain is exceedingly fine, and 

 the structure compact, the fracture being at the same time splintery 

 and conchoidal. It is translucent at its fine edges and previous to ex- 

 posure to the atmospheric action its color is generally blackish blue, 

 passing, when highly polished, into a deep and beautiful black. 



Lime, silex, and alumine are its chief component parts, the latter 

 being in such quantity that its upper beds, whenever they are laid 

 bare, turn of a whitish hue, and rapidly change into a tenacious 

 marie. 



The specific gravity is very low, (2.5) and it is, as already stated, 

 saturated with carbon, and deeply impregnated by oxidulous iron. 



These types, with its magnetic pyritous iron, in which the arse- 

 nical variety is mingled, and the presence of sulphuret of zinc, par- 

 ticularly of yellow blende,* associated with magnesian calc spar, and 

 magnificent specimens of sulphate of strontian and barytes,f together 

 with the comparative absence of all organic relics, those which are 

 found, being of the oldest genera, and its extraordinary relations to 

 the newer granitic aggregates, and the smallness of its dip, assuredly 

 complete its claim to the character of a limestone, of the elder tran- 

 sition family. 



* Which has been recently discovered in it by Mr. Baddely, and which is indica- 

 tive of the oldest formation of zinc. 



t By a singular mistake, these beautiful specimens, which are very numerous, 

 have always been called tremolite here, owing to the hasty dictum of a traveller, 

 who should have known better. Their weight caused me to doubt, when I was 

 first shewn them, and analysis soon rectified the error. Tremolite is very rare here. 



