213 



CONGLOMERATE ROCKS. 



The name of these renders any description of 

 their characters unnecessary ; and, for the dis- 

 tinction of the varieties, the reader must have re- 

 course to the Synopsis, 



VEIN STONES, 



These also require no observations ; since, 

 being attached in some way to the rocks in which 

 they lie, or depending- for their essential distinc- 

 tions on their geological position, they are neces- 

 sarily recognized. Like the conglomerate rocks, 

 they are formed of distinct portions of different 

 substances. 



APPENDIX 1st and 2d. 



VOLCANIC ROCKS. 



The resemblance of many of these to the over- 

 lying rocks, renders it also necessary to be ac- 

 quainted with their geological situations. These, 

 in fact, are always known, from the circumstances 



