240 NEW YORK STATE MUSEUM 



partly fragments of the mother rock and partly pieces of the crystal- 

 line wall lining or a continuous laminated deposit of the calcareous 

 red sand which composes the rock itself. Where broad, the veins 

 are still open and lined with calcite crystals. 



It is very obvious that these secondary fissures have been built 

 in a different way than the primary. Torn-off parts of old fissure 

 linings and bits of the rock itself may have got into them with 

 the process of rending the strata, but the laminated sand deposits 

 which completely fill the veins over a considerable extent can have 

 come only from the washing into the open fissure of the sand 

 resulting from the meteoric decomposition of the rock itself. It 

 is to be conceived that these secondary fissures opening across the 

 strata when exposed to weathering agencies, received from the wash 

 of the rain, etc., the red limestone sand which now fills them. 



The inference, therefore, is that however ancient the primary 

 series of fissures may be, the secondary series is of relatively late 

 origin. 



The torsion stresses in these rocks are indicated by the photo- 

 graph on plate 31. 



