234 On the Transition Rocks of the Cataraqui. 



it is- not now deemed necessary to. introduce, as the others are suffi- 

 ciently explanatory. 



Limestone of so very ancient a class, being formed into prismatic 

 shapes, so similarly to basalt, but taking a nearly horizontal position, 

 presents a new feature in geology, and although at first sight, it might 

 go far to prove the theories which have been advanced concerning the 

 igneous origin of the Cataraqui rocks in its vicinity, yet on a more 

 careful examination of them, it does not appear to justify those the- 

 ories, or to cause me to waver from the opinion originally given, 

 that the Cataraqui granitic rocks are of an age assimilating to the 

 transition limestone, with which they are so closely connected, and 

 the singular appearance this lithographic limestone has here assu- 

 med, in a limited locality, may be traced satisfactorily to the same 

 causes which have made the greenstone of Lake Superior associa- 

 ted with sienite to assume the columnar form, which is at Kingston, 

 after all, perhaps, merely a modification of cleavage on a grand 

 scale, or a mere deviation from ordinary appearances, similar to the 

 beautiful minute columnar limestone of the adjacent beds which we 

 have already described, and which may as well be brought forward 

 to testify that these enormously thick masses of horizontal fossilifer- 

 ous rocks owed their origin to volcanic agency. 



In fact, I see nothing after several years experience, to alter the 

 opinions which have been assumed by the geologists already advert- 

 ed to, that these are granitic rocks of the families posterior to the 

 primary class, and I think that these opinions are very strongly as- 

 sisted and developed in Upper Canada, from the extremity of Lake 

 Superior to the shores of the United States, near the Thousand 

 Islands of the St. Lawrence, and in further investigating this very 

 interesting subject, I shall hereafter endeavor to undertake a descrip- 

 tion of the Lacustrian chain, under which term is embraced the 

 ridge which bounds Superior, Huron and the ancient shores of On- 

 tario, and endeavor to prove that the primary rocks scarcely exist 

 in this chain, which appears to me to be of a much more recent 

 date than that class, and to have owed its origin to the same influ- 

 ence which formed the transition rocks of the Cataraqui, and has 

 been but little affected by that igneous agency which created the 

 decided trappose masses, occasionally blended with it, and I am the 

 more inclined to support this opinion, from the absence of mica, ei- 

 ther schistose, or forming a considerable share of ingredients in the 

 granitic aggregates of this immensely long chain, which strikes across 



