FIFTH REPORT OF THE DIRECTOR I908 



" surface thrusts" (Willis). As an example we insert a portion 

 [text fig. 31] of the Rome (Ga.) folio, showing inliers of Cambric 



Fig. 30 



wood formation) ; 



Wedge inlier from Briceville folio, Term. j jjij.'^jy 



Devonic (Chatanooga shale); 



Siluric (Rock- 

 Z-zr£~ Carbon- 



iferous (Lee conglomerate) ; 



Carboniferous (Briceville shale). Scale 



r^cks in Carboniferous beds, appearing as small synclines, but 

 which in fact, as shown by the section are but the erosion remnants 

 of a huge, closely folded overthrust plate of the kind that has been 

 so much discussed in late years by the Alpine geologists [their 

 " Ueberschiebungen " or " charriages," sec text fig. 32]. 



It is possible that the slate belt of eastern New York represents 

 such an overthrust region of the first order. We see the strongest 

 arguments for this view in the long fault that separates the Lower 

 Siluric and Cambric rocks east of the Hudson which is known to be 

 an overthrust fault; and in the fact that in several places, as most 

 clearly near Whitehall, the littoral facies of the Cambric and Lower 

 Siluric (Potsdam sandstone, Beekmantown dolomite and Trenton 

 limestone) and the graptolite-bearing shale facies of the same 

 formations come into contact, which implies — granted the original 

 separation of the two facies by either a barrier or differences of 

 depth — an extensive westward transportation of the shales. If 



