rl02 



NEW YORK STATE MUSEUM 



should be, approximately plain and featureless, but quite the 

 reverse. 



On the one hand, the uneven surface of the pre-Cambrian rocks 

 indicates a relatively rapid transgression of the sea, too rapid to 

 permit of its reducing the land to a structureless submarine plain. 

 The occasional coarse, poorly assorted conglomerates, with very 

 angular pebbles, also point to the same conclusion. On the other 

 hand, the prevailing homogeneity of the sandstone and the com- 

 plete absence of arkose suggest slow accumulation and a perfect 

 assorting. 



The only satisfactory explanation is that already given — a very 

 complete weathering prior to the submergence; and such 

 weathering, in which chemical changes were dominant, is to be 

 correlated, as Merrill 1 has suggested, with a warm and humid 

 climate. But even with a deeply weathered, superficial layer 

 there must have been, lower down, a zone of partially weathered 

 rocks, which would furnish arkose material, to be disposed of in 

 some way. 



To the writer it seems probable that the time required by the 

 sea to cut a plane surface may be much greater than that re- 

 quired under favorable conditions to decompose and disintegrate 

 arkose material, and that thus, while a plain erosion surface 

 ought theoretically to be covered by a purely quartzose sand, an 

 uneven surface may also be covered by such a deposit. Certainly 

 Daubree's familiar experiment suggests that such decomposition 

 and disintegration must be very rapid under shoal water con- 

 ditions; while the cutting of a submarine plane must be a very 

 slow process. 



The present topography of the region shows, as already stated, 

 a very close dependence on the geology, and varies from point to 

 point, as the underlying rocks change. 



A region of schists, limestones and quartzites like that east of 

 Eedwood, is very rugged with steep ridges, cliffs, and deep nar- 

 row valleys. The maximum relief is moderate, but the irregu- 

 larity is excessive, being a result of the varied resistance offered 



'Rocks, rockweathering and soils, p. 283. 



