331 



RED PRIMARY SANDSTONE. 



THIS is now for the first time introduced into 

 a catalogue of rocks. An abstract of the reasons 

 for this innovation may be deduced from the 

 sketch of its geological connections which fol- 

 lows. A more full account of the history of this 

 interesting member of the primary strata, is inad- 

 missible in this work ; but it will be found in 

 the authors' volumes already quoted, where an 

 ample detail is given of the evidence which jus- 

 tifies the arrangement here adopted. 



If the specimens are sometimes not very dis- 

 tinguishable from those which are found in the 

 lowest sandstone of the secondary class, the geo- 

 logical nature of this classification did not the less 

 demand the present proceeding ; which is, more- 

 over, strictly analogous to that, long since admit- 

 ted in the case of limestone ; ill which rock, a 

 distinction between the examples found in the 



