M11 GYPSUM. 
Sulphate in the well waters is derived from these, and these are 
usually in the New Red Marl. We now go farther afield to the best 
known localities in the neighbourhood, where the massive variety of 
Gypsum is observed, and where it is mined or won. The denser 
varieties known as alabaster, to be used in internal decoration for 
altars, pulpits, pillars, mural tablets, etc., and I have seen recently 
statues of the early Roman period, the drapery of which consists of 
dense massive variegated Gypsum, probably from Castelino, but it 
may be from Fauld, for reasons which I shall mention later. The 
less dense and more or less crumbled pieces are ground, and by the 
processes known as “baking” or “boiling” converted into Plaster of 
Paris, which is also employed for decorative purposes. It is not 
necessary that I should occupy your time by describing the above 
processes, or the property that the “baked” or “boiled” plaster 
possesses of “setting” when mixed with a definite quantity of water, 
whereby mouldings and castings of various kinds are obtained. 
Many of us have had the pleasure of visiting the Fauld works 
more than once. To those the occurrence of the mineral need not be 
described. We can all well call to mind how the Gypsum appeared 
in the strata, now no longer worked. We can readily remember the 
whitish masses, irregularly embedded in the marl, not existing in 
layers interstratified with it, but in irregular embedded masses of 
various sizes, Then, when we visited the interior of the mine, we 
were brought face to face witha similar condition of affairs, only that 
the embedded masses were immensely larger. How were these 
masses placed where they are? That is thechief point to which I 
wish to draw your attention to-night. Were they brought there, 
dissolved in water, and deposited in layers? If so, they would be 
crystalline, not massive, and if they were so deposited in the inter- 
spaces now occupied by marl and dissolved, or washed away by the 
action of water, we should find some evidence of continuity in the 
spaces and should get some evidence of bedding, but I have been 
unable to obtain any evidence of this description. The masses are 
not crystalline, neither are they regularly arranged, but are scattered 
