294 NEW YORK STATE MUSEUM 



any possibility of completing this process for now the nearest out- 

 crop of the red conglomerates and sandstones is some rods away 

 and below the level of these fissures. 



This purely mechanical filling of a fissure is in its process unlike 

 many of the recorded examples of sand veins and dikes where the 

 filling has resulted from normal deposition of sand on an eroded 

 and fissured surface. The writer has described the case of the 

 Oriskany sand penetrating to fissures in the underlying Siluric 

 rocks at Buffalo, X. Y. Many parallel and far more striking cases 

 of similar character are known and have been described by va- 

 rious writers, Diller, Cross, Geikie, Pavlow, but the case here de- 

 scribed differs from these in the evident filling of the fissure, not 

 at the time of deposition of the overlying sandstone deposit, but 

 at the time of its erosion, through the action of a small infiltering 

 surface current. This conclusion is fairly established by the vacant 

 upper cavities of the fissure indicating an entire removal of the 

 supply of material before the filling of the cavity was complete. 



