GYPSUM. 112 
through the marl in practically the same way as were the mountain 
limestone boulders in the marl and clay on the top of the Outwoods 
cutting ; in fact, if we could convert these limestone boulders into 
Gypsum, we should have exactly the same appearances as obtained 
where the massive Gypsum is worked for plaster and Alabaster at 
Fauld. 
Of course, if there were vast beds of massive Gypsum amongst 
the hills of Derbyshire, it would be conceivable that these masses 
were conveyed from the source in the same way as the limstone on 
the Outwoods was conveyed, viz.: by glaciers or icebergs, but there 
are no such beds; and, furthermore, we have the fact of the solubility 
of Gypsum in water to contend with. We have, therefore, to 
speculate as to the means by which these vast masses of Alabaster 
attained their present position, and whence their component materials 
were derived. 
There can be no doubt that during the elevation of the high 
lands of Derbyshire, and since they acquired their present height a 
large amount of denudation took place, and is still taking place, but 
we have to deal more particularly with the past. Further, it is 
quite clear that, although broken here and there and thrown out of 
place by the upheaval, the strata lying on the flanks of the limestone, 
Kast and West, North and South, viz.: the Yoredale Slates, the Mill- 
stone Grit, Coal Measures, Breccia Sandstone, Magnesian Limestone, 
were denuded with the formation of the red and grey sands, the Red 
Marl, and the Rhaetic bed, and some at least of the Lias. Most of 
this denudation was subaqueous, and there must have been 
at least two glacial periods, one immediately after the Magnesian 
Limestone period, or at least after the deposition of the grey and red 
sandstone. At the close of this it would seem that the high ground 
of Derbyshire was covered with ice, which extended from North to 
South, and terminated in the water from which the red and grey 
sands, etc,, were deposited, with a contour into the waters beginning 
at somewhere near Cheadle, thence to Uttoxeter, Tutbury, by Burton, 
