88 On the Transition Rocks of the Cataraqui. 



ite, as the micaceous ingredient is almost, or perhaps entirely, want- 

 ing in the transition rocks of tlie Cataraqui. But although there is 

 every reason to be adduced in favor of other terms, inasmuch, par- 

 ticularly, as most other mineral compounds have received distinct 

 names, yet the relative ages of the granitic rocks are still so Httle un- 

 derstood, that we shall, in obedience to the all powerful sway of cus- 

 tom, continue thus to style them. 



In the neighborhood of Kingston, certainly, the micaceous ingre- 

 dient of a true granite disappears in the various aggregates of which 

 the more ancient rocks consist, but still the positions assumed by 

 modern geologists concerning primary and subsequent formations 

 of granites, is strikingly exemplified in the very singular distribution 

 which nature has here made of her mineral resources. 



It is asserted that the presence of tin, magnetic iron, hornblende, 

 garnet, talc and chlorite, replacing mica, as well as a tendency to pass 

 to pegmatite, characterise the newer formations of that substance, 

 which had heretofore been considered as the oldest of all known 

 mineral matter, and that primitive euphotlde,* posterior to clay slate, 

 is placed at the limit of primitive and transition formations, a com- 

 pact grayish limestone passing to fine grained, connecting the eupho- 

 tide of Scandinavia, according to Humboldt the last member of the 

 primitive family, with very ancient intermediary rocks. The same 

 indefatigable geognost candidly observes, however, that it is as diffi- 

 cult to fix the ages of euphotides as it is those of granites, and that 

 those which he saw at Guanaxuato, Cuba, and Mexico, and at the. en- 

 trance of the Llanos de Venezuela, connected with syenite or black 

 liniestone, appeared to him to he as decidedly transition as those of 

 the Bochetta of Genoa, stratified and imbedded in the transition clay 

 -slate which alternates with black limestone. f Anthracite is also said 

 to bear the same relation to the transition as graphite does to the 

 primitive and coal to the secondary formations, whilst the frequent 

 presence of hornblende and the comparative absence of quatt?:, are 

 also distinguishing marks between the first and the intermediary 

 t^lasses. According to Jameson, schorl is rarely associated with 

 hornblende, and from the testimony of Cleaveland we learn that 



* A mixture of diallage, jade and lamellar felspar, of which scrpenlinite is a va- 

 liely, with small grains of an homogeneous aspect 



t De Buck and Brochant couf^idercd the euphoUdes of Spczzia, Prate and the 



whole of the Sienuesc, as primitive, whilst BiiojvoNiART asserts that they arc sec 

 ondary, or of a very recent Iransition class. 



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