56 



KEY. J. MILNE CURRAN. 



The accompanying map will give a general idea of the geology 

 of the district. The rocks chiefly represented are granite, 

 porphyry, clay-slate, sandstones, and limestones, the latter as 

 freshwater and recent, and Silurian. There is nothing in the 

 geology of the neighbourhood to explain the origin of the spring. 

 It rises through sandstones, but none of these are calcareous. 

 There is no basalt nearer than a few miles, and the point of 

 eruption must be still further away. A Silurian limestone crops 

 out about half-a-mile to the south-east, but it has no apparent 

 connection with the spring. The fact of the outlet being so close 

 to the junction of porphyry and sedimentary rocks demands some 

 attention. The igneous rock has been intruded amongst the 

 stratified rocks, and no doubt the water finds its way to the 

 surface along one of the many rents and fissures formed by the 

 intruding mass. The spring is however, of comparatively recent 

 origin, while the porphyry is to say the least pre-tertiary. 



The following analysis was made in duplicate in my own 

 laboratory and on samples of the water collected by myself : — 



Grains per Gallon. 



Total solids at 100° 10304 



Silica 1-47 



Ferrous oxide 



Lime 



Magnesia 



Soda 



Potash ... 



Chlorine... 



Sulphur trioxide 



Carbon dioxide (fixed) ... 



Combined water 



Less " oxygen equiv." to CI. found 



•19 



35-00 



5-18 



5-53 



.4-27 



5-88 



1-16 



34-86 



10-75 



104-29 



1-25 



103-04 



