GYPSUM. 110 
Gypsum is found in the interior of fossil shells, in veins and 
crevices, but it is always easily recognisable by its softness—it can 
be scratched with the finger nail—by its solubility in water, and by 
giving the reactions for lime and sulphuric acid. In our locality I 
have not seen any large distinct natural crystals of Gypsum, and only 
here and there in very minute forms. In the massive and crystalline 
state, as I have said, it is abundant. There can be no doubt that 
the massive form is the source of the crystalline and crystallised 
ones. 
Let us look around, and we shall soon satisfy ourselves as to the 
nature and form in which Gypsum is found in our locality. Go to 
the brick yards at the south side of Ashby Road, and between it and 
Waterloo Clump, standing out here and there, we observe pieces of 
clay containing layers of whitish material lying horizontal on the 
beds of clay, which all around have been removed ; then, here and 
there we observe veins of the same material running down at more 
or less inclined angles to the horizon. (Gypsum mixed with clay does 
not make good bricks). If we go to the hill-face, to the left and 
south of the Outwoods Recreation Ground, we observe the same thing, 
only that, inasmuch as, the marl was required for railway ballast, 
and not for brick making, the beds are not so obvious although the 
veins are numerous. While we are at this place we find on closer 
observation in the mar] at the top of the cutting a layer of boulders, 
large and small, of Derbyshire limestone, many indeed of which can 
be traced to their native beds in that shire. To the west of this 
cutting the South Staffordshire Waterworks Co. some years ago 
excavated a reservoir, now covered in, and when this was being made 
vast boulders of limestone were found embedded in the mar. I call 
your attention especially to this fact as it has to do materially with 
the idea I am going to submit to you to-night as to the position of 
Gypsum. 
In well boring in our locality the auger frequently passes through 
crystalline Jayersof Gypsum. A considerable quantity of the Calcium 
