1863.] 291 [Lesley. 



The reverse is true of erosion above water-level. Steepness of dip is 

 favorable to aerial disintegration, to the dissection of stratification, to 

 the subdivision of one massif into several, and of one hillock into 

 many ; hence to the general degradation of the surface under air. 

 But under water the reverse is true. 



In the Laurentian and Huronian, Scandinavian or Azoic regions of 

 the North, where distortion and plication have revelled from the be- 

 ginning to reduce things to anarchy, and where alternate potash 

 rocks and limestones form the boldest contrast of endurance and 

 decay, lakes abound. A clean, smooth drainage system, worked out 

 so completely (without stating the agency) as to leave no holes, nor 

 cul de sacs pointing in the wrong direction, nor crooked lakes, is 

 possible only when the .stratification is clean and in good order, cut- 

 ting equally and smoothly in all directions according to the force, 

 and permitting the law of compensation to have free course in the 

 establishment of a common and gently declining niveau of reference 

 to water-level. But any conceivable erosive agency, cataclysmic or 

 secular, must encounter a million contretemps, in smoothing oif its 

 work over a country like Canada, where no outcrop runs fir without 

 doubling like a hare. Sir William Logan has shown that the crooked 

 lakes and lake-like rivers of that country conform to the plications 

 of the primary limestone belts. 



Mr. Ball's own hypothesis of an original fault structure for the 

 lake system of the Alps is not new, and is open to as much objection 

 on other grounds, as the theory of Professor Bamsay which he over- 

 throws. If applied to the Devonian lake system of New York and 

 Pennsylvania, and therefore, of course, to the thorough-cut valley sys- 

 tem of the Carboniferous plateau of the Alleghany Mountains of 

 Northern Pennsylvania, it will not find a fact to stand upon. Not a 

 trace of fault structure is to be seen over all that immense region ; 

 yet the erosion is in straight lines, north and south, and from five 

 hundred to a thousand feet deep. Also not a trace of original glacial 

 action can be found. Diluvial striae are rare ; moraines and taluses 

 are wanting. Not one has yet been recorded, if any exist, nor have 

 I ever seen throughout that region, any resemblance to one which 

 did not resolve itself on examination into a barrier outcrop, slightly 

 masked by soil or local drift; and even instances of this kind are 

 rare. 



On the other hand, throughout that whole region, the Lyellist 

 can find no evidence of a slow wear and tear through the ages. The 

 region is swept too clean for that. There are no piles of detritus, no 



