GENERAL GEOLOGY OF THE DISTRICT. 445 



schists are most strikiiig. These facts impress one so strongly that it is safe 

 to say that no one can pass through this experience without having the 

 conviction forced upon him that there is a great structural break l^etween 

 the quartz-slates and the complex series to the south. Such a general rela- 

 tion, it seems to lue, is more significant than tlie <lirect al)utment of the 

 schistose structure of one rock against auotlier; more significant than 

 actual structural breaks seen by the eye iu an\' single exposure; more sig- 

 nificant than any basal conglomerate; yet, as will be seen, all of these 

 suboa-dinate proofs of unconformity have been found at various places in 

 this district. 



The above paragraph contrasting the lithological cliaracters and strati- 

 graphical relations of the Southern Complex and the Quartz-slate is applica- 

 ble with almost equal force to the relations of the Southern Complex and 

 Chert}- limestone. The only modification that need be made is that the 

 Cherty limestone is not so continuous as the Quartz-slate, so that one is not 

 so strongly impressed with the absolute necessity for a discordance between 

 tlie two in order to adequately explain their field relations. 



' The relations of the eruptive massive syenites and granites to the 

 adjacent schists and to the Cherty limestone and Quartz-slate are such as to 

 show that the schists and massive rocks are vastly older. That the granites 

 should intricately intersect the schists and yet for man}' miles be immedi- 

 ately adjacent to the Cherty limestone and Quartz-slate, yet never cut 

 them, is inconceivable on any r)tlier hypothesis than that they were in this 

 position before the deposition of that belt of rocks. It is, further, all but 

 universally believed that the coarse grained granites and syenites are a 

 class of rocks which have crystallized under great pressure and therefore 

 at depth. If this be true they must have been subjected to great erosion in 

 order that the Cherty limestone and Quartz-slate could have been deposited 

 directly upon them, and they are therefore immensely older than the latter 

 rocks. The indejtendent relations, also, of the green schists to the quartz- 

 slates are such as to show- that between them is a great interval of time. It 

 has been said that the fibers of the schist run iu every possible direction and 

 that in certain cases the\- al)Ut directly against the slates. These schists 

 may be eruptive or fragmental, but in either case their schistose structui'e 



