538 HISTORY OF GEOLOGY. 



We may remark here already how generally 

 there are mingled with descriptive notices of such 

 geological facts, speculations concerning their causes. 

 Herodotus refers to the circumstance just quoted, 

 for the purpose of shewing that Egypt was formerly 

 a gulf of the sea ; and the passage of the Roman 

 poet is part of a series of exemplifications which 

 he gives of the philosophical tenet, that nothing 

 perishes but everything changes. It will be only 

 by constant attention that we shall be able to keep 

 our provinces of geology distinct. 



Sect. 2. Early Descriptions and Collections of 

 Fossils. 



IF we look, as we have proposed to do, for syste- 

 matic and exact knowledge of geological facts, we 

 find nothing which we can properly adduce till we 

 come to modern times. But when facts such as 

 those already mentioned, (that sea-shells and other 

 marine objects are found imbedded in rocks,) and 

 other circumstances in the structure of the earth, 

 had attracted considerable attention, the exact exa- 

 mination, collection, and record of these circum- 

 stances began to be attempted. Among such steps 

 in Descriptive Geology, we may notice descriptions 

 and pictures of fossils, descriptions of veins and 

 mines, collections of organic and inorganic fossils, 

 maps of the mineral structure of countries, and 

 finally, the discoveries concerning the superposition 



