64 



tlie rocks tliroTigli which the water makes its way to the 

 surface. It is almost unnecessary to say that there are no 

 traces of recent volcanic action anywhere in the district. 

 Of the sedimentary rocks of the neighbourhood, none are 

 older than the Upper Palaeozoic, and the volcanic rocks asso- 

 ciated with them belong, probably, to an epoch immediately 

 succeeding the carboniferous period.* 



