XORMAL FAULTING IN VIRGINIA PIEDMONT 347 



In regard to the structure of the Triassic in Connecticut, Davis* says : 

 "The faults must affect not only the Triassic but must penetrate east- 

 ward, westward, and downward into the crystalline floor on which the 

 strata rest It seems advisable to attach considerable im- 

 portance to this explicit expansion to this problem of deformation, so 

 that it shall concern not only the Triassic but the crystalline schists as 

 well." Shaler and Woodworthf, in discussing the same question relating 

 to the Richmond, Virginia, Triassic area, remark: "That these basins 

 are due to deformation of the underlying granitic terrane by faulting seems 

 highly- probable." Keith|, in discussing the structure of the Catoctin 

 belt, remarks: "Doubtless Newark structures are present in the Catoc- 

 tin belt, but the means are not at hand for detecting them. The Catoctin 

 belt is defined by one of the Newark faults along its eastern limit. Other- 

 ^ase its manifestations are confined to the Newark belt itself." 



The results obtained in the Fauquier-Culpeper slate area strengthen 

 the probability of a wider distribution of Newark structures in the Appa- ' 

 lachian belt than has formerly been supposed. Since the crystalline rocks 

 of the Piedmont belt are here cut extensively by normal faults in various 

 directions, which are only made recognizable by a thin mantle of well- 

 defined Cambrian strata, and since the writers § and others have observed 

 similar structures in the Shenandoah group of limestones in the Great Vallej' 

 province west of the Blue Ridge, it is very likely that further investigations 

 will reveal normal faulting more widely distributed in the Appalachian 

 province. 



* Davis, W. M., Triassic Formations of Conliectiout, 18th Ann. Rept., United 

 States Geological Survey, pt. ii, p. 141, 1896-97. 



t Shaler, N. S., and Woodworth, J. B., Geology of the Richmond Basin, Vir- 

 ginia, 19th Ann. Rept., United States Geological Survey, pt. ii, p. 487, 1897-98. 



t Keith, Arthur, Geology of the Catoctin Belt, 14th Ann. Rept., United States 

 Geological Survey, pt. ii, p. 355, 1892-93. 



§ Watson, Thomas L., and Cline, Justus H., Petrology of a Series of Igneous 

 Dikes in Central Western Virginia, Bull. Geol. Soc. Amer., 1913 (in press). 



