166 The Lincolnshive Keuper Escarpment. 
way in which it affected his ‘ Fens and Floods.” ‘The Cliff at 
Newton is remarkably picturesque, and the Lincolnshire 
Naturalists’ Union held one of its most interesting meetings there 
this year. 
As before stated the portions of the escarpment which remain 
at the present time owe their durability, for the most part, to the 
gypsum they contain. This mineral, which is an aqueous deposit, 
found in many sedimentary beds, is formed, and is being formed 
in the present day, in a variety of ways. It is usually white, but 
in places it gets stained with impurities and becomes dirty-look- 
ing and dull, or red and yellow when discoloured by iron oxide. 
Sir Archibald Geikie, in his text book, mentions several modes in 
which it may be formed—such as “ a chemical precipitate from 
solution in water, as when sea water is evaporated ;” or from the 
decomposition of sulphide acting on limestone; or through the 
action of sulphurous vapours upon calcareous rocks, &c. ; and it 
is to the first of these methods that the gypsum in the Keuper 
Marls owes its origin, for the Keuper once formed the fringe of a 
large inland sea, or salt lake, which has left traces of its former 
condition in the pseudomorphous crystals, filling up the cavities 
which the true salt crystals once occupied; many of which are 
found in those parts of the escarpment which have been dug into 
and disturbed. 
Gypsum occurs in various forms on the line of the Lincolnshire 
escarpment. On the north of Gainsborough it appears as fibrous, 
satiny bands. At Gainsborough, and on the south of the town, we 
meet with it in granulated rubbly masses, interstratified with 
layers of hardened sandstone. [T'urther south it lies in isolated, 
saccharoid nodules, which.are highly soluble ; (so much so that I 
once saw a good sized block, which was lying exposed on the 
Railway bank, pierced, ina short time, clean through by the con- 
tinual drip, drip, from the cornice of a bridge above it), while in the 
Newton Cliff, as the photograph above referred to shows, it occurs 
in lenticular bands and veins running in all directions, some of 
which frequently cross and intercross one with another, producing 
a remarkable, but not uncommon, effect. 
Had the escarpment all along the line, being fortified and 
