^8 
W. Pengelly on the Red Sandstones, 
distinguishable from that further west by the presence of ovoid 
hollow geodes beautifully lined on the inner surfaces with crystallized 
carbonate of lime. Some of them are upwards of a foot in mean 
diameter ; they generally lie with their longest axes parallel to the 
plane of stratification, and in many cases they coincide with the 
bedding surfaces. They are not equally abundant in all parts of 
the cliff, being most numerous, and perhaps largest, about midway 
between the town and the hill, and decreasing in frequency in a 
more marked manner towards the east than towards the west. 
These beds also contain nodular masses of a greenish or 
blueish-green matter, which are sometimes more than a foot in 
diameter, and quite distinct from the greenish circular patches 
previously mentioned. The latter are true marl, distinguishable 
from that surrounding them by the difference of colour only ; they 
have the appearance, as has been already stated, of marl from 
which the prevalent chocolate colour has been discharged, and are 
no more capable of being extracted from the general mass, in their 
integrity, than is a rust spot from an otherwise highly-polished 
steel blade. The nodules just mentioned, on the contrary, are 
readily separable from the marl beds in which they occur ; they 
differ from the latter in composition also, being rather arenaceous 
than argillaceous, nevertheless they have not the aspect of incor- 
porated sandstone pebbles. By way of illustration, rather than of 
explanation or hypothesis, it may be said that they suggest the 
idea that they are masses of sandy matter segregated from the 
general material of the beds. White mica is frequently abundant 
in them, and also in the deposit generally on this part of the coast. 
Immediately west of Sidmouth a projecting part of the cliff is 
composed exclusively of sandstone of the bright brick-red so pre- 
valent about Dawlish. It is separated from the marl, with the 
duller colour of which it is strongly contrasted, by a line of frac- 
ture, possibly of fault, and contains a very fine example of 
remarkably complex false stratification. This mass is probably 
a relic of a series of sandstone beds which once occupied the broad 
