52 ALTERATION IN THE 



between the strata of two consecutive geological 

 systems ? How came it that after the last mem- 

 ber of a geological system had been deposited, the 

 strata of that system shifted from a horizontal 

 position to one so much inclined to the horizon that 

 the first member of the subsequent formation was 

 deposited upon the edges of those strata ? Was it, 



FIG. 15. 



B 



that during the interval which elapsed between the 

 deposition of one geological system and the com- 

 mencement in the deposition of another the next 

 in succession the sun was darkened ; and as the 

 earth during the period in which the solar rays were 

 withdrawn would radiate heat to distant space, and 

 receive no heat ab extra in return, the globe would 

 suffer so great a diminution of temperature that its 



