102 



HISTORt" OF 



eause. Tliey allege, that mountains have been formed merely 

 because they are useful to man. This carries the inquirer but a 

 part of the way ; for no one can aifirm, that in all places they 

 are useful. The contrary is known by horrid experience, in 

 taose valleys that are subject to their influence. However, as 

 the utility of our earthly habitation is a very pleasing and flat- 

 tering speculation to every philosopher, it is not to be wondered 

 that much has been said to prove the usefulness of these. For 

 this purpose many conjectures have been made, that have re- 

 reived a degree of assent even beyond their evidence ; for mei! 

 were unwilling to become more miserably wise. 



It has been alleged, as one principal ad^•antage that we de- 

 rive from them, that they serve like hoops or ribs, to strengthen 

 our earth, and to bind it together. In consequence of this the- 

 ory, Kircher has given us a map of the earth, in this manner 

 hooped with its mountains ; which might have a much more 

 solid foundation, did it entirely correspond with truth.* 



•According to Werrrr, the rocks of which this globe is composed, as far aa 

 they have been penetrated below the surface, ainouut to 3G, and they all (jc- 

 cupy a determinate position with respect to each other. They extend round 

 the whole earth, and inclose the central nucleus like the coats of an onion. 

 Not that they are every where spherical, or uninterrupted: partly on ing 

 to inequalities in the centre nucleus, over which they are deposited, and 

 partly to oHier causes, they rise higher in one place, and sink lower in an- 

 other, sometimes slowly, and sometimes abruptly; and they are entirely 

 wanting in many particular spots, having either never been deposited, or hav- 

 ing been removed and carried away by some unknown cause. The position 

 oi the ditferent rocks being thus constant, has been pitched upon as the basiS 

 cf the classification of them. They have been divided into live classes; and 

 the t?Tm formation has been applied to them, from the supposition that each 

 class has been formed about the same time. Those rocks which lie lowest 

 iown, or nearest the central nucleus, belong to the first or primitive forma, 

 tion ; and those which lie highest up, or immediately at the surface, belong 

 to the fourth or latest formation ; for the fifth formation includes only the 

 volcanic matters, and of course is confined to particular spots. The names of 

 the formations are as follow: I. Primitive. 2. Transition. 3. Floetz. -1. Al- 

 luvial, 6. Volcanic. We are not to suppose, however, that the rocks be- 

 longing to the primitive formation are always at a great depth below the sur- 

 face. On the contrary, they frequently constitute mountains ; and the liighest 

 mountains on the surface of the earth are composed of them. In these cases we 

 must suppose the subsequent formations either never to have been deposited, 

 or to have been removed and carried off by some unknown means. In like man- 

 ner, the transition and floetz formations often constitute mountains, and appear 

 ■t the surface ; and this must be accounted for in the same way. The primi. 

 tive formation consists of rocks which follow others in sufcessieu ia the or. 



