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XXVII T. Report on a Manuscript IVork of M. Andre, 

 formerly known wider the Name o/*P. Chrysqlogue dk 

 Or, entitled A Theory of the actual Surface of the Earth, 

 By MM, Hauy, Levierre, and Cuvier. Read to 

 the Class of Mathematical and Physical Sciences in the 

 National Institute*. 



As this is the first opportunity which has hitherto presented 

 itself of entertaining the class with geological subjects, it will 

 not perhaps be considered foreign to our purpose to make some 

 general reflections on the manner in which a society such as 

 ours may and ou<>ht to consider this kind of researches. 



The natural history of unorganized bodies, commonly 

 called crude matter, or minerals, is divided into two principal 

 branches. In the one we examine each of these bodies by 

 itself, and in its physical and chemical properties, and hence 

 determine its distinctive characters, and its rank in the ge- 

 neral system. This part has more particularly retained the 

 name of mineralogy, which has almost always been culti- 

 vated by men of talents, and has now attained a degree of 

 precision and exactness, equal, at least, to that of all the 

 other physical sciences. 



The object of the other branch of the history of minerals 

 is the reciprocal position of their different species, and of 

 the masses composed of one or more of these species. It is 

 this branch which teaches us what materials constitute the 

 vast extent of countries, what others are confined to vacan- 

 cies, crevices, and fissures of the preceding; it shows us 

 what substances respectively form the great chains, inferior 

 mountains, ridges, and plains ; it is especially occupied with 

 the super-position of minerals, and enables.us to distinguish 

 between those which always bear,* and those which always 

 surmount others, or, in a word, to discover the order of the 

 different strata. To this branch is given the appellation of 

 geology , geognosy, or physical geography, according to the 

 extent and profundity of the researches. - 



It is evidently a science susceptible of as much accuracy 

 as mineralogy properly so called. To give it this quality, 



* From Transactions of the Institute, 1808. 



it 



