524 GEOLOGY. 



ments should have been in progress about the borders of the conti- 

 nents ever since, and that there should have been built out from the 

 borders a systematic series of Paleozoic, Mesozoic, and Cenozoic ter- 

 ranes, forming a distinct fringing zone. In this zone we might expect 

 to find the most complete of all the stratified series, embracing repre- 

 sentatives of all the ages and all the transitions, for on the borders of 

 the continents sedimentation should rarely, if ever, have been wholly 

 interrupted. This theoretical deduction is so strong that its verity 

 can scarcely be doubted. 



But an inspection of the geology of the coast-belts, as at present 

 exposed, reveals the significant fact that not only is this theoretical 

 deduction far from realized, but that the stratigraphic series is there 

 singularly imperfect, indeed much inferior to that of the continental 

 interiors. 1 The northeastern coast of North America and nearly 

 the whole coast of Greenland are formed of Archean and Proterozoic 

 formations, and the whole of the later series is essentially wanting. 

 From Newfoundland to New York, the coast formations are mainly 

 divided between the pre-Paleozoic and Paleozoic, with very scant 

 representation of the Mesozoic and Cenozoic eras. From New York 

 southward, Mesozoic and Cenozoic terranes have a fair, but not impres- 

 sive development, while the Paleozoic are scarcely identifiable outside 

 of the crystalline belt. On the west coast there is an intricate series, 

 much interrupted by crystallines of more or less doubtful ages, which, 

 if it could be fully interpreted, might more nearly fulfill theoretical 

 expectations; but this is uncertain. In South America, long stretches 

 on the northeast and southeast borders consist of crystalline rocks of 

 ancient aspect, save for narrow tracts of younger beds on the immediate 

 coast. There is no suggestion of a great systematic series. The eastern 

 coast-tract of Patagonia more nearly meets expectations relative to 

 the later periods, in that it constitutes a wide sloping plain of sedi- 

 ments heading at the Cordilieran axis on the west, and dipping beneath 

 the Atlantic on the east; but this seems to be rather an extension of 

 the interior plain of the La Plata basin than a typical fringing 

 series. On the west side of South America, crystalline rocks, some 

 of older, some of younger age, form complex terranes along or near 

 the coast throughout more than half the length of the continent, while 



1 The geological maps in Berghaus' Physical Atlas afford the means for such an 

 inspection. 



