3'74 
ELEMENTS OF GEOLOGY. 
times raagm- 
fiied. Riley and 
Stutchbury. 
Dolomitic con- 
glo m e rate. 
manner in which the teeth were implanted in the jawbone, 
obtained great celebrity because the patches of red conglom^ 
erate in which they were found, near Bristol, were originally 
Fig. 396 . supposed to be of Permian or Palaeozoic age, 
and therefore the only representatives in Eng¬ 
land of vertebrate animals of so high a grade 
in rocks of such antiquity. The teeth of these 
saurians are conical, compressed, and with finely 
serrated edges (see Fig. 396); they are referred 
by Professor Huxley to the Dinosaurian order. 
Origin of Red Sandstone and Rock-salt. — In 
Tooth of Theco parts of the world, red and mottled 
dontosaurusf% clays and sandstones, of several distinct geo¬ 
logical epochs, are found associated with salt, 
gypsum, and magnesian limestone, or with one 
or all of these substances. There is, therefore, 
Redimid, near in all likelihood, a general cause for such a co- 
incidence. Nevertheless, we must not forget 
that there are dense masses of red and variegated sand¬ 
stones and clays, thousands of feet in thickness, and of vast 
horizontal extent, wholly devoid of saliferous or gypseous 
matter. There are also deposits of gypsum and of common 
salt, as in the blue-clay formation of Sicily, without any ac¬ 
companying red sandstone or red clay. 
These red deposits may be accounted for by the decompo¬ 
sition of gneiss and mica schist, which in the eastern Gram¬ 
pians of Scotland has produced a mass of detritus of precise¬ 
ly the same color as the Old Red Sandstone. 
It is a general fact, and one not yet accounted for, that 
scarcely any fossil remains are ever preserved in stratified 
rocks in which this oxide of iron abounds; and when we find 
fossils in the New or Old Red Sandstone in England, it is in 
the gray, and usually calcareous beds, that they occur. The 
saline or gypseous interstratified^beds may have been pro¬ 
duced by submarine gaseous emanations, or hot mineral 
springs, which often continue to flow in the same spots for 
ages. Beds of rock-salt are, however, more generally attribu¬ 
ted to the evaporation of lakes or lagoons communicating at 
intervals with the ocean. In Cheshire two beds of salt occur 
of the extraordinary thickness of 90 or even 100 feet, and ex¬ 
tending over an area supposed to be 150 miles in diameter. 
The adjacent beds present ripple-marked sandstones and foot¬ 
prints of animals at so many levels as to imply that the whole 
area underwent a slow and gradual depression during the 
formation of the red sandstone. 
Major Harris, in his ‘‘Highlands of Ethiopia,” describes a 
