Bernard Smith—Upper Keuper, Hast Nottinghamshire. 303 
has been mapped and described once more,’ but in no case has 
particular attention been paid to the composition and structure of 
the sandstones of the Keuper Marls, which are usually dismissed 
by writers in as few sentences as possible. The following notes 
collected between 1906 and 1910 may therefore serve a useful purpose 
in supplementing previous descriptions of the Marls, and may throw 
light upon the probable method of accumulation of this somewhat 
monotonous formation. 
Surface Features.—The sandstones of the Keuper Marl of Notting- 
hamshire are locally known as ‘skerries’, and the relief and 
characteristic appearance of the outcrop is directly due to these 
‘skerries’ with their associated beds—a combination which I shall 
refer to as ‘skerry-belts’. In the almost complete absence of drift 
the marls have weathered in such a way that practically every feature 
is the expression of some resistant bed which may be quite invisible 
at the surface. In rare cases this may be a hard blocky marl, but 
usually it is a skerry-belt. 
If the Keuper Marl plateau, where least dissected, is followed in 
the direction of the dip, the successive skerry-belts encountered— 
unless individual skerries are very thick and hard—do not make 
much show, but come on gradually, first the lower layers and then 
the higher ones. When, however, the plateau is well dissected, 
the beds forming the belt stand out boldly, especially where the 
strike-streams trench the upland close to the now well-developed 
escarpments. 
In the north-eastern part of the county the lower skerries form 
an upland gently sloping in an easterly or south-easterly direction 
drained by dip-streams flowing to the Trent. Standing upon one 
of the divides between the valleys and looking north or south, ridge 
after ridge, supporting village after village, may be seen at the same 
level. From this level the slopes drop in steps over successive skerry- 
belts to the valley bottoms, the edge of each remnant of the upland 
being the edge of the valley upon that side; hence the characteristic 
scenic effect is the straight sky-line, whether in long ridges or isolated 
hills. 
Skerry-belts—The skerry-belts—usually about 6 feet thick—are 
composed of alternations of micaceous sandstone, shale, and marl with 
occasional veins of fibrous gypsum, and are unexpectedly persistent, 
although individual beds of stone may occasionally thin out whilst 
others become thicker. 
The sandstones vary from an exceptional thickness of 3 feet to less 
than half an inch, the thicker beds being often split up by sandy 
shales. In the belts it is common to find (in upward succession) red 
marls and clays followed by a thin layer (1-2 inches) of green and 
blue clay, which is sueceeded abruptly but conformably by a sandstone. 
Above the latter there is a gradual passage through green to green- 
red and finally red clays and shales. Pseudomorphs after salt crystals, 
formed at the surface of the green-blue clay, are frequently found on 
the bottom surface of the sandstone. The sandstones are pale in 
1 “The Geology of the County between Newark and Nottingham’’: Mem. Geol. 
Sury., 1908, pp. 35-54, and in Swmmaries of Progress for 1907-8. 
