4 



an angle of 51° high up, 52° lower down, 53° just over the 

 the mountain, and still steeper where it descended to the 

 present surface of the country, that is, along the line where 

 the vertical rocks are covered by the limestones dipping 

 uniformly about 54°. 



It seems impossible to resist the conclusion that this dip 

 of 54° shows that the whole mass of Palaeozoic formations 

 on the east, about 20,000 feet thick, rose and rode up the 

 plane formed by the basset edges of the mass upturned 

 vertically on the western side of the fault, and rested thereon 

 at an angle due to the bevel of the western mass, a bevel 

 geometrically determined by the shearing movement among 

 the members of the upcurved western mass. 



Mr. Lesley considered the discovery of much importance 

 for structural geology, and that it may prove to be the first 

 real step towards a satisfactory conclusion respecting the 

 slope, or underground (and in the air) angle, of great faults ; 

 also proving the negative against a common belief that the 

 great anticlinals of disturbed regions must be reconstructed 

 in air sections as if gaping. It lends great support also to 

 the doctrine of vast erosions, a doctrine taught by Pennsyl- 

 vanian geologists for many years, and more recently contended 

 for by Jukes, Ramsay, Geikie, and other advanced geolo- 

 gists abroad, on unimpeachable and irresistible evidence. 



The report of the Judges and Clerks of the Annual 

 Election was read, by which it appeared that the following 

 officers and members of Council had been elected : 



President^ 

 George B. Wood. 



Vice-Presidents^ 

 John C. Cresson, Isaac Lea, Frederick Fraley. 



Secreta7'ies^ 



Charles B. Trego^ E. Otis Kendall, John L. LeConte, 

 J. P. Lesley. 



