LECTUEE III 



History of the doctrine of Geological Succession Lehmann, Fuchsel, 

 "Werner The spread and decline of Wernerianism D'Aubuis- 

 son, Von Buch. 



THE most casual observation suffices to convince us that 

 the surface of the earth has not always been as it is to-day. 

 At one place we recognize, in sheets of sand and gravel, 

 proofs of the former presence of running water, where none 

 is now to be seen. Elsewhere shells and other marine 

 organisms underneath the soil prove that the dry land was 

 formerly the bed of the sea. Masses of sandstone, con- 

 glomerate and limestone, once evidently laid down in 

 horizontal layers on the sea -bottom, but now hardened 

 into stone, disrupted, placed on end, and piled up into 

 huge hills and mountain-ranges, show beyond all question 

 that stupendous disturbances attended the conversion of 

 the sea-floor into land. 



These proofs of former revolutions on the surface of the 

 globe are so abundant, so easily comprehended and so 

 convincing, that some of them early attracted notice. The 

 frequent references to them, in the literature of ancient 

 as well as modern times, prove how familiar they have 

 been from the dawn of civilization. They have suggested 

 many cosmologies and theories of the earth, for there has 



