362 
DAVIS : MINEKAL WEALTH OF HAEROGATE. 
the stratum of shale, and has a lateral motion which is only diverted 
upwards when it approaches the borehole or fissure, if it rises throug-h 
one. 
These different densities are not the result of an undisturbed 
condition extending" over a long period of time, but are quite 
recently produced, as the samples were taken 36 hours after the 
borehole had been well stirred up in clearing* it of accumulated mud. 
The practical applications of these facts have a sig-nificance to 
Harrog-ate and its Spas, which is not of the same import elsewhere, 
unless situated in the region of mineral waters. 
Suppose a well to be sunk in a part of Harrogate, to a depth of 
18 to 20ft., where the conditions to be spoken of exist, the alluvial 
deposit will first be penetrated, then perhaps sand, afterwards yellow 
clay, then a blue or almost black clay is reached, after which is the 
black shiver or shale, the upper part finely laminated, and which, as 
the excavation proceeds, becomes harder and of a more rock-like 
character almost like slate, by this time sulphur water will probably 
be reached. 
The characteristics of the water met with in these proceedings 
will be found as variable as the strata. There is first the surface 
water containing carbonate of iron in solution to a more or less degree; 
when the blue clay is penetrated a weak saline water charged with 
iron either as carbonate or in some other combination makes its 
appearance ; and as the excavation continues the water becomes 
more saline and less chalybeate ; eventually a zone is touched of 
strong saline water containing only traces of iron ; and proceeding, 
these traces disappear, and a saline sulphur water is reached. Of 
course these differences are gradual. 
It is obvious that any excavation in the vicinity of such a well 
as I have described, if it allows the water bearing strata to discharge 
into a drain, culvert, or any other continuous outlet, will perma- 
nently let down these stratified waters ; to increase the number of 
wells will also have a sensible effect upon the first well sunk, unless 
there is some peculiar geological formation which prevents this 
occurring, even the frequent emptying of a well will in some 
instances temporarily reduce the strength of a water, which, how- 
