59 



draw various conclusions with resfard to several of these con- 

 ditions , and in a hiter chapter the most important results 

 will be given. As, however, the mineralogical constitution of 

 the samples may also tend to account for the manner in 

 which the deposits obtained their material, it will be neces- 

 sary first to make this the subject of a closer examintion. 



