242 On the Transition Rocks of the Cataraqui. 



primary and transition rocks of the eastern states on the one side, 

 and with the same classes on Lake Superior on the other, classe-s 

 distinguished in the granitic families by the absence of mica, the 

 presence of amphibole, the abundance of feldspar, and the facility 

 with which it appears to have passed into greenstone, rendering it 

 questionable whether it has ever been connected with what has 

 hitherto been termed the primary rocks. 



Captain Bayfield, in his excellent succinct account of the geology 

 of Lake Superior, which he enjoyed the enviable advantage of ex- 

 amining under favorable circumstances, is of opinion that the green- 

 stone of Lake Superior, which occurs in immense beds, forming per- 

 pendicular and columnar precipices upwards of a thousand feet in 

 altitude above the great lake, and which passes into sienite and what 

 he terms sienitic granite, should not be confounded with the trap, 

 greenstones, and sienitic masses, associated with the amygdaloids 

 and porphyries, and which in general occupy, excepting in veins, a 

 comparatively lower situation, from the circumstances of its alterna- 

 ting with and sometimes overlying the granite, and from appearances 

 of stratification in it, as well as its forming chains of hills and im- 

 mense beds. 



That it should not be classed with the overlying rocks, the trap, 

 greenstones, amygdaloids, and clay porphyries, is very evident, but 

 as, according to Dr. Bigsby, and from what Capt. Bayfield observed, 

 as well as the appearances in the sienite of the Cataraqui of stratifi- 

 cation, it can scarcely be said to belong to the primary family, and 

 may, therefore, with much probability, come under the transition, 

 submedial, or Hemilysian era, particularly if any facts can be sub- 

 stantiated which connect it with the known limestone strata of that 

 epoch. 



And in order to pursue this investigation, we shall again visit the 

 shores of the Cataraqui, and endeavor to find amidst the never end- 

 ing varieties of the amphibolic rocks there, whether or no such facts 

 are to be elicited. 



The sienite, of a bright red color, which has been already men- 

 tioned as forming a large mass of the Kingston rock, and as being 

 joined as it were to the transition trilobitic limestone, exhibits some 

 remarkable features, both on Cedar Island, and on the main land, 

 in the township of Pittsburgh. 



Here, as we have already stated, the sienite actually penetrates 

 the limestone, and that in a very remarkable manner, without hav- 



