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PROCEEDINGS OF THE GEOLOGICAL SOCIETY. .April 4,
Fig. 5.
Beds of Rock Salt in Red Sandstone.
Nor is it an easy matter to account for its occurrence, for not only is
it in a very elevated position, but the basins themselves are too isolated
and of too limited an extent, to allow us to attribute the formation of
the salt to the evaporation of the water of the ancient sea, on the
elevation of these rocks above the surface. A more probable solution
is, that these basins became the receptacles of salt springs which
flowed into them from the surrounding hills, in which the saline
matter may have been chemically produced by the effect of gases
entering the red sandstone in consequence of igneous or volcanic
agency. Not being a chemist, I throw out this suggestion with much
hesitation, but I cannot account for the pheenomena in any other way.
May we not imagine that muriatic vapours, coming in contact with
the soda contained in the felspathic elements of the marls, would
enter into combination with that basis and produce the requisite saline
matter 1 I must also observe, that wherever I have had an opportunity
of examining the analyses of natural saline springs, T have invariably
found that the chlorine or muriatic acid enters into combination mth
the soda, but not with the potass even when it is present. Thus,
whatever may be the opinion of chemists as to the greater affinity of
the chlorine for potash than for soda, it would appear that in the
great laboratory of nature such is not the case.
The other principal element of this formation consists of a yellow-
ish sandy marl containing numerous masses and crystals of selenite,
sometimes passing into distinct beds of sands and clays equally full
of similar small crystals. Mr. Ainsworth describes this formation
as constituting very extensive uplands, and evidently saw it deve-
loped on a larger scale than I did. In the neighbourhood of Vizier
Keupri it forms the low undulating hills of the plain, which rest against
the older semicrystalline limestone. The low hills which surround
the plain of Tchorum also consist of it, containing masses of cal-
careous marl besides the crystals of selenite. I nowhere had an op-
portmiity of discovering any fossils in this formation.
It also occurs to the west of the elevated and vertical ridge of red
sandstone west of Soungourli, where it forms low hills, horizontally
stratified, on the left bank of the Delhiji Su. Again, to the south-west
of Sevrihissar, after entering the great horizontal formation of Central