THE PRE-ADAMITE EARTH. 



So that the total thickness of the formation is above 12000 feet, 

 or 2g miles, the chief part being occupied by the first or lowest stage. 

 The mineral composition of these stages will be stated when we 

 come to notice them separately. 



399. While at some points these seven stages are found in 

 regular superposition, in others particular stages are absent. 

 Thus, while on the northern and eastern border of the Anglo- 

 Parisian basin the series is complete, in other localities great dis- 

 cordances of stratification are observed, as well by the varying 

 dips of the contiguous strata as by the absence of one or several 

 stages of the series. These are the grounds upon which the entire 

 Cretaceous formation is stratigraphically set apart from the 

 Jurassic, and upon which the seven stages into which it is resolved 

 are inferred to be independent, and those conclusions are con- 

 firmed by observations made upon the arrangement of the depo- 

 sition of the organic remains, which appear to be distributed in 

 seven distinct layers, corresponding with the stratigraphical 

 limits of the stages. 



