On the Transition Rocks of the Calaraqui. 93 



It is the general appearance of some of the porphyroid and syenitic 

 groups which most tends to mislead an enquirer who has a natural 

 bias towards the vulcanian theory and doubtless there are many 

 cases, in which even the most impartial geognost would not only be 

 in extreme doubt, but would at last, probably give up the examina- 

 tion in despair, especially in some of the syenites which bear strong 

 marks of fusible conversion. 



At Kingston, the syenite range, we have mentioned, is of very 

 little, or scarcely any comparative elevation, above the surrounding 

 strata of calcareous matter, and excepting where sharp vallies have 

 been worn or disrupted for the passage of waters, has every where, 

 a low wave like outline and surface. Its denudation moreover, is 

 extremely limited and it is usually bounded by a vast accumulation 

 of superjacent and decidedly transition limestone, the strata of 

 which, from the level of the lake to about the altitude of one hun- 

 dred and twenty feet, vary, in a generally decreasing ratio, from six 

 feet in thickness, to about eight or ten inches, their upper beds, in 

 many instances, being covered, by a fissile shale, very calcareous, but 

 which is converted into a muddy clay by the action of the weather, 

 whilst several of the superior and some of the inferior layers have 

 very thin seams of clay interposed, and a great proportion of all the 

 beds are separated by an extremely fine, black, bituminous looking 

 substance, which is also of the shale kind, and the whole are marked 

 by minute veins of calcareous spar, which often traverse their lon- 

 gitudinal direction, and cause them to assume the aspect of a lami- 

 nar rock. 



It has been argued, as we have already noticed, that the transition 

 granitic rocks of the Cataraqui (which are almost every where cov- 

 ered by this limestone, but whose basis has never yet been seen) 

 from their wave like and rounded surface, from the singular intermin- 

 glement and conjunction which takes place between them and large 

 portions of the limestone strata, and from the particular circumstance of 

 a part of these calcareous beds, dipping from its sides at high angles, 

 was formed by igneous agency under the enormous pressure of the 

 great ocean which, doubtless, once rested over this division of the 

 new world. A very attentive and zealous observer who has recent- 

 ly made these rocks a favorite study, in conjunction with the writer 

 of this essay, is so much impressed with this idea, that it would be very 

 difficult to convince him that it may not be the case, notwithstanding 

 the circumstance that the calcareous mass for miles around, and indeed 



