90 



OUTLINES OF GEOLOGY. 



of its waters, 'which had risen high on the sides, if not to 

 the tops, of the most lofty mountains. It is yet a question 

 whether there had been one or more of these catastrophes. 

 It is obvious, that if a deluge were to pass over the present 

 surface, the loose diluvium and alluvium now existing would 

 be mingled and confounded with the deposits of such a flood. 

 Th b<e is one instance already known, in which a bed of di- 

 luvial gravel has been disturbed by a change in the form of 

 the rocks beneath, and is covered in part by a similar bed of 

 less thickness, which has not been disturbed. This is suffi- 

 cient to show that two successive floods have prevailed in 

 that place. A few more observations of the same nature, 

 at remote distances, would prove that two deluges had oc- 

 curred, instead of one.* 



The large size of many of the diluvial boulders, as well 

 as the abundance of the deposit in many places, shows that 

 the action of the waters must have been intense ; while the 

 small degree of attrition which they have met with, shows 

 that the catastrophe must have been of short duration. 



The phenomena of erratic blocks have been plausibly ac- 

 counted for, by supposing that the deluge, rising to the tops 

 of lofty mountains, had floated thence the glaciers, with the 

 masses of rock imbedded or adhering to them. These 

 glaciers, grounding on the subsidence of the waters, and 

 melting, may have left these blocks in the places they 

 now occur. As the largest and best known blocks are de- 

 rived from the Swiss and Norwegian Alps, this hypothesis 

 is far from improbable. 



197. The coal measures have unquestionably been depo- 



*This view of the subject is most consistent with the Mosaic record, which de- 

 scribes the earth at the lime of the creation as covered with water, besides recording 

 a subsequent deluge ; and with the fact that by far the greater part of the remains of 

 terrestrial animals, found in diluvium, belong to extinct species, would be reconciled 

 with the record of the preservation of animals at the deluge of Noah. 



