587 



ON VEINSTONES. 



As these are frequently causes of doubt, or 

 sources of difficulty, to inexperienced geologists, 

 it will not be superfluous to give a slight sketch 

 of them after the conglomerates, to which they 

 are so nearly allied. When they are found in 

 veins, they readily explain their own origin ; but 

 they sometimes occur m situations where their 

 real connections cannot be traced, and may thus 

 be confounded, without due attention, with the 

 more general conglomerates, or, occasionally, 

 even with the compound rocks that form exten- 

 sive beds. In a work that aims to be useful 

 without pretending to be rigidly systematical, the 

 allotment of a place for these accidental sub- 

 stances will be excused. 



The larger veins which occur among rocks, 

 are commonly filled with fragments of the includ- 

 ing strata, united with various minerals, earthy, 



