MINERAL VEINS. 409 



a provision, entire Coal fields might be occasionally burnt 

 out and destroyed. 



It is impossible to contemplate a disposition of things, so 

 w^ell adapted to afford the materials essential to supply the 

 first wants, and to keep alive the industry of the inhabitants 

 of our earth ; and entirely to attribute such a disposition to 

 the blind operation of Fortuitous causes. Although indeed 

 it be dangerous hastily to have recourse to Final causes, 

 yet since in many branches of physical know^ledge, (more 

 especially in those which relate to organized matter,) the 

 end of many a contrivance is better understood, than the 

 contrivance itself, it would surely be as unphilosophical to 

 hesitate at the admission of final Causes, when the general 

 tenor and evidence of the phenomena naturally suggest 

 them, as it would be to introduce them gratuitously unsup- 

 ported by such evidence. We may surely therefore feel 

 ourselves authorized to view, in the Geological arrange- 

 ments above described, a system of wise and benevolent 

 Contrivances, prospectively subsidiaiy to the wants and 

 comforts of the future inhabitants of the globe; and extend- 

 ing onwards, from its first Formation, through the subse- 

 quent Revolutions and Convulsions that have affected the 

 surface of our Planet. 



CHAPTER XXI. 



Advantageous Effect of Disturbing Forces in giving Origin 

 to Mineral Veins:* 



A FARTHER rcsult attending the Disturbances of the sur- 

 face of the Earth has been, to produce Rents or Fissures 

 in the Rocks which have been subjected to these violent 



* See PI. 1. Figs, fe l.—k 24, and PI. 67. Fig. 3. 

 VOL. I. — 35 



