166 c. schuchert the, xorth americax geosyxclixes 



Geanticlines 



(See Map. Figure 2) 

 DAXA'S VIEWS 



Having seen that '^synclinoria were made through a progressing geo- 

 synclinal," we are brought, Dana states/^ "to another important distinc- 

 tion in orographic geology — that of a second kind of monogenetic moun- 

 tain/' These are ^^rodnced through evolving geanticlines, which "are 

 simply the upward bendings in the oscillations of the earth's crust — the 

 geanticlinal waves/' or "anticlinoria." His typical example is the Cin- 

 cinnati arch, though it is perfectly clear that later on he included far 

 greater and even continental (epeirogenic) arching under the term anti- 

 clinoria. Beginning with simple, depressed, and restricted arches, the 

 term came to be applied by Dana to all upward archings of lesser and 

 greater extent. 



"Geanticlines and geosynclines,'" Dana states/^^ "are flexures of the strata 

 of the earth's exterior, or the supercrust. not of the crust itself. The crust is 

 thick, and it is impossible, were it but 10 miles thick, that it should be bent 

 into so small and abrupt flexures. It has. however, its own great flexures of 

 low angle and of great breadth, both upward and downward."" 



CIXCIXXA TI GEAXTICLIXE 



The Cincinnati uplift of Xewberry and Safford, and the Cincinnati 

 plateau of H. S. Williams, was defined by Dana in 1890^^ as the type 

 example of a geanticline. It has in a general way the strike of the Appa- 

 lachian folds and was at times overlapped in part or wholly by the 

 Appalachian or Mississippian seas. When the medial part was submerged, 

 the northern end made Cincinnati Island and the southern one Tennessee 

 Island. As two swells, the arch appeared in Middle Ordovician time,, 

 was repeatedly reelevated, and during the middle and late Paleozoic con- 

 tinued as a marked structural feature of the Mississippian seas. It had 

 a width of something like 250 miles. 



XE^y BRUXSWICK aSAXTICLIXE 



To the south and east of the Saint Lawrence geosyncline lay the Xew 

 Brunswick geanticline, separating it from the Acadian trough. This 

 geanticline appears to have originated at the time when the Saint Law- 



1' Dana : Amer. Jour. Sci. (3). vol. 5, 1873. p. 432. 

 1^ Dana : Manual of geoloT.v. 4tb ed.. ISO.i. p. 100. 



^'' Dana : Areas of continental progress in North America. This Bulletin, vol. 1. p. 41. 

 Also Manual of geolog.v, 4th ed., 1805, p. 387. 



