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the state of the surface as to the relative propor- 

 tions of primary and secondary rocks at the time 

 they were deposited. Although, therefore, strictly 

 appertaining to the secondary class, their dates, 

 or connexions, might not be discovered by their 

 position, merely in one part. But if the same 

 continuous mass is found to cover, interfere with, 

 or ramify into a primary and a secondary rock 

 also, there is to be obtained, even when in the 

 former connexion, a proof of its appertaining to 

 the secondary class. 



It has been just remarked, that the surface of 

 the earth bears marks of waste, and that this 

 waste is necessarily most sensible in the upper- 

 most rocks, other circumstances being equal > As 

 the secondary unstratified rocks under review, are 

 the uppermost, they consequently exhibit the most 

 extensive and remarkable losses of substance. It 

 thus happens in nature, that masses of the unstra- 

 tified rocks are found insulated on the surface of 

 the stratified, or, in other ways, occupying dis- 

 tinct and detached positions. It must therefore, 

 also occasionally happen that they will be found 

 connected with the primary rocks only, in the 



