[ i84 ] 

 QUARTZYTHS AND QUARTZ-ROCKS. 



BY G. H. KIXAHAN, M.R.I. A. 



( Concluded from p. i66.) 



Part II.— Quartz ytks. 



As already suggested, the great difficulties in connection with 

 the quartzytes are to discover marks and tokens by which their 

 exact terrane can be determined. 



Experience teaches that in all the tracts of each dififerent 

 geological age there are certain peculiarities common to all, 

 although in some areas much more prominent than in others. 

 I have, however, the audacity to believe that after lengthened 

 and careful field study, I can determine in any special area, in 

 the field, but not from hand-specimens, the age of the different 

 quartzytes ; but, at the same time, it would be hard to explain 

 the reasons by which I come to my conclusions, so that rarely 

 have I been able to convince any of my colleagues that the 

 differences between the different rocks were quite plain to me. 

 The late Prof Carvill Lewis was able at once to see and ap- 

 preciate the proofs, but he had studied in America. 



After the examination and study of a section, I have sat down 

 on a mass of quartzyte, and stated to my comrade: "These 

 quartzytes are thousands of 3^ears older than those," pointing 

 to a cliff a hundred yards away. I have lit one pipe, two pipes, 

 even six pipes of tobacco, while he has been wandering about 

 and collecting perfectly uninstructive specimens. Of course, 

 when he presented them to me and defied me to point out the 

 differences between them and the quartzyte I was sitting on, I 

 could not do so, as his collection was made solely to illustrate 

 details, not the masses.' When he was pointed out the speciali- 

 ties of the older rocks, his reply was, "Oh, I will show the 

 same in your newer rocks!" This, of course, after repeated 

 attempts he failed to do. The above describes what takes 

 place when in the field with those geologists who would 

 make the rocks suit their preconceived ideas, instead of 

 their conclusions being founded on what the rocks prove. 

 Such geologists have, however, this excuse — it is no child's 

 play to give definitions by which one quartzj^te can be dis- 

 tinguished from another, as is illustrated b}^ the long time it 

 has taken to disentangle the geology of the Great I^akes Dis- 

 trict in the United States and the Dominion in America. 



In this area, for years, the Potsdam Sandstone, and the con- 

 formably underlying quartzytes, were supposed all to belong 



^ Since the above was written, Prof. Winchell in his preHminary report 

 on the ancient rocks of Minnesota draws attention to the difference 

 between the study of rocks "in masses" and "in detail." 



