Massive Crystalline Rocks. 163 



A B represents a portion of the schist near the granite ; B to C, 

 soda-granite ; C to D, coarse syenite-like diorite ; D to E, soda- 

 granite; a to /, the bands, which are lettered as in the above de- 

 scriptions of them. 



Fig. 15. 



ABC D E ' 



a b c d e f 



The depth to which the beds are made to descend downward in 

 the granite (100 feet) is an assumption in this section ; but con- 

 sidering that probably 5000 feet, and more likely over 10,000 feet 

 of these upturned rocks have been removed by erosion, and noting 

 also the number of the bands and their parallelism to the schist, and 

 the effect of pressure to keep them in place, the assumption can be 

 no exaggeration. 



Since it is obviously impossible that the inclusions taken in and 

 carried up by rocks erupted through deep fissures should be beds of 

 schist 100 to 200 feet long, and a series of such beds separated by 

 the fused rock retaining together their parallel position, we have to 

 admit that these indications of bedding are of unohliterated bedding. 

 The rest of the upturned strata were fused or at least softened ; these 

 portions of beds were not fused, though flexed and variously displaced. 



There is reason for the resistance to fusion in the mineral nature 

 of the beds ; for quartz, staurolite, fibrolite, magnetite, are infusible 

 minerals ; muscovite and biotite are but slightly fusible on thin 

 edges ; and orthoclase fuses with great difficulty, much greater than 

 the other felspars, oligoclase, labradorite and alljite. 



Thus the studj'' of the phenomena of contact becomes in this 

 region a study of " inclusions "; and the larger of the inclusions turn 

 out to be beds of schist, conformable to the schist. 



We seem to be thus forced to the conclusion that the soda-granite 

 and the included diorite were once parts of the same sedimentary 

 strata with the schist, and that all, with the Cruger limestone, were 

 once a continuous stratified formation ; and that the plasticity given 

 to the granite-making or diorite-niaking portions, because of the 

 heat, occasioned the exceptional geological features of the region. 



The region of Cruger's Point is continued northward into that of 

 Montrose Point ; the latter is characteiized, as has been stated, by 

 chrysolitic rocks for its southern three-fourths, and by norite with 

 chrysolitic rock for the otluer fourth ; and through the facts there as 

 well as elsewhere afforded, the evidence from inclusions is made to 

 extend also to these other rocks. With the chrysolitic pyroxenite 

 and chrysolitic hornblendite, there is also hornblendite which is not 

 chrysolitic, but more or less augitic, and containing some triclinic 



