1822.] _ Mr. Weaver's Geological Remarks. 85 
dients of the old red sandstone, we shall find them referable to 
the detritus of those tracts, and varying in different quarters. The 
cement which combines these ingredieuts is usually siliceous, or 
an indurated sandy micaceous clay ; it is more rarely marly, but 
it contains in general so much oxide of iron as to take a brown- 
ish-red colour, whence, as Freiesleben observes, the name of the 
rock, the rothe todtliegende, the red dead lier, has been derived, 
although beds of greyish and whitish colours are not unfrequent. 
The sandstone formation itself is described by Freiesleben as 
- consisting of conglomerate, breccia, sandstone, slaty micaceous 
sandstone, indurated slaty clay, and clay marl, in beds frequently 
alternating with each other, from a few inches to several ells, 
and even fathoms, in thickness ; but, generally speaking, they 
are from two to four feet thick. 
The conglomerate usually forms thick beds in alternation with 
fmer grained and clayey beds, but sometimes appears in the 
form of thin layers in fine grained sandstone. It constitutes the 
least part of the formation, being commonly situated in the 
lower region. The boulders and pebbles vary from the size of 
one foot in diameter to that of a nut, compacted by smaller 
grained ingredients of the same composition, with brownish-red 
ironshot indurated sandy or marly clay, which is more rarely of 
a white cast and calcareous quality. The rounded and angular 
fragments noticed by Freiesleben are claysiate, taleslate, flinty 
slate, lydian stone, greywacke, gneiss, trap, porphyry, quartz, 
hornstone, jasper, and agate, with disintegrated felspar, grains 
of quartz, and mica, differently assembled in different parts of 
the range; for the minute detail of which, as well as of the fol- 
lowing beds, I must refer to the copious work of that author.* 
The breccias and sandstones exceed in mass the conglomerate, 
and extend to a greater distance from the fundamental rock. A 
common form of the fine grained breccia is that of angular grains 
of quartz, with single pebbles of quartz and hornstone, and 
numerous small fragments of yellowish-white decomposed fel- 
spar, and scales of mica; sometimes also including single frag- 
ments of ironshot clayslate, or talcslate, the whole being 
combined by a brownish-red sandy cement. Sometimes also 
small grains of reddish-white decomposed felspar predominate, 
which, with grains of quartz, are imbedded in a sandy clayey 
slaty base of a dark cherry-red colour. The small and fine 
grained sandstones vften appear of a homogeneous character, and 
either granular or slaty, brownish-red or grey, more rarely white, 
sometimes also alternately striped red, grey, and white, or with 
a reddish-grey or bluish base, containing white spots. In the 
most uniform sandstone appear occasionally streaks or layers of 
* In this composition of the conglomerate, we perceive a close analogy to that of 
some parts of Ireland noticed by the writer of this article, e. g. adjoining Waterford 
Harbour. (Geol. Trans. vol. v.) Some of the conglomerates also closely resemble those 
ef the old red sandstone of Tortworth and Milbury Heath, in Gloucestershire. 
