Transactions of the Geological Society. 
181 
shall confine ourselves, therefore, to such extracts as are less dependant on preced- 
ing statements, or may more easily he illustrated. 
“ The promontory called theOrd of Caithness, which constitutes the north east- 
ern termination of the deposits of the Oolitic scries in Sutherland, has been de- 
scribed as a granitic rock composed of much felspar and quartz, with a substance in 
a decomposed state which may have been mica. Now although such is the pre- 
valing character near its junction with the secondary strata, an examination carried 
on more in the centre of the mass has detected so many examples of well crystalliz- 
ed mica, that this rock must be considered a true granite.” 
“ In the previous memoir I stated, that wherever this rock comes in con- 
tact with the beds ol' the Oolitic series, the latter are compounded into a remark- 
able breccia : and recent observation has not only fully confirmed the conclusion 
which I drew from these phenomena, viz. ‘ that the granite of this coast must have 
been elevated at a period subsequent to the deposition of the Oolitic strata,’ but 
has also led Professor Sedgwick and myself to the conviction, that it has been up- 
heaved in a solid form, and that, in breaking through those submarine deposits 
which might not perhaps have been originally in contact, it has so fractured and 
dislocated their beds as to have prepared them for reconsolidation in the state of a 
brecciated rock.” 
Consistently with this opinion it is found that “ where the granite disappears, a 
more full development of the secondary strata would take place, and such is the 
case in this district ; for with the recession of the granitic ridge, the regular forma- 
tion of the Oolitic series, from the sandstone of the calcareous grit down to the 
base of the inferior Oolite, arc laid open, including the coal field of Brora,” 
In some remarks on the Sutors of Cromarty lie states, that what he had supposed 
in his first paper to be granite he found, on a closer examination, consisted chiefly 
of a feldspathose and quartzose gneiss, much foliated and generally nearly vertical ; 
but in many situations so decomposed as not to be distinguishable from some 
varieties of the granite of the Ord of Caithness. This gneiss is associated with sub- 
ordinate slaty rocks hornblendic and talcose, and is repeatedly traversed by large 
and small veins of true granite,” 
“ Many writers have contended (and it seems now to he pretty generally admit- 
ted), that the granite must have been in a iluid state at the period when these veins 
issued from its mass ; and others have further presumed, that the gneiss must then 
also have been in a state of softness. But in whatever mode these ramifying and tor- 
tuous veins in primary rocks may have been produced, a very different explanation 
is requisite to account for the fractured and brecciated beds of the Oolitic series 
which accompany the elevation of the granite on the coast of Sutherland. There, 
it is evident, that the granite, when uplieaved, could not have been in a fluid state, 
since it has neither penetrated nor overflowed the contiguous masses of solid brec- 
cia ; in such situations, therefore, the disturbing rock was at the period of its eleva- 
tion most probably in a compact and crystalline form ; in which case, when forced 
up against the overlying strata, it must have fractured the sandstone, limestone, and 
shale, thus preparing" the materials which, when recemented, formed the breccia above 
described. But we have additional evidence of the elevation of the granite, en masse, 
upon this N. E. coast of Sutherland, where it has not only brecciated the beds of 
the Oolitic series but lias also thrown up the red conglomerate to the summits of 
many of the mountains whose bases consist either of granite or of gneiss charged 
with granitic veins. In these positions the old red conglomerate which, when undis- 
turbed, passes beneath the Oolitic series and its coalfield of Brora, presents that 
anomalous appearance which without explanation might lead to the supposition of 
its being an overlying deposit. , „ , 
Amongst some remarks on the denudation of Braambury and Hare Hills we find 
the following : “ I remarked in my former paper that these hills probably owe tlicir 
present form to denudation ; which supposition is now confirmed by the exposure 
on their surf re of innumerable parallel small furrows and irregular scratches, both 
deep and shallow, such, in short, as can scarcely have been produced by any other 
operation than the rush of rock fragments transported hy some powertul current. 
Upon my first visit these markings being only imperfectly visible in one situation near 
the quarries,! was unwilling to enlarge upon the fact jbut Mr, Barton, the director 
of these works, has since cleared away the turf from other parts of the surface, and 
these operations have uniformly exposed similar phenomena, ' And again “These 
appearances so closely resemble those in other places described by Sir J, Hall and 
Dr, Buckland, that further detail seems unnecessary ; and the large slabs which I 
have had the pleasure of presenting to the Society, completely elucidate the case*” 
