48 ALTERATION IN THE 



FIG. 13. 



Now these strata, with their inflections, were they 

 extended and restored to their original horizontal 

 position, would be subtended by a horizontal base 

 three times greater than that which they now sub- 

 tend. Whence this contraction of base? Is it 

 because the magnitude of the globe was very much 

 greater when the strata of gneiss were deposited 

 than it is now, and therefore the strata, if soft by 

 virtue of the lateral pressure induced by the con- 

 traction of the circumference of the globe, would 

 undergo bendings and inflections while accommodat- 

 ing themselves to the nucleus of a globe, which 

 ceased not to diminish in magnitude ? Is it thus, that 

 the horizontal base which subtended the strata of 

 gneiss during the period of their deposition was so 

 much greater than that which they now subtend ? 



75. If so, what was the magnitude of the globe 

 at the period when gneiss, the first of stratified 

 rocks, were deposited ? 



76. Sir James Hall, in the "Edinburgh Phil. 

 Transactions," vol. vii., has made a representation of 



