260 MR. GARDINER AND PROF. REYNOLDS ON [May 1902, 
(5) Rhyolites not showing nodular or banded struc- 
ture.—Several varieties of these rocks are met with. The most 
important is perhaps the hard compact purple rock (A 11) which 
forms the prominent flow to which Redcliff Cove owes its name. 
This has a cryptocrystalline groundmass, somewhat iron-stained. 
It shows no lenticular patches coarser-grained than the rest. Fel- 
spar-phenocrysts are abundant, and often show corrosion by the 
groundmass. They exhibit, however, no sign of a general parallel 
arrangement, and often appear broken, so that the section presents 
features which suggest an ash. As already mentioned, when de- 
scribing this rock in the field, this is also suggested by the occurrence 
of included xenoliths of rhyolite. 
In the inlet of Carrignaneena, on the south side of Doon Point, 
occurs a compact purple rhyolite (C 12), quite unlike in character 
any of those of the Clogher-Head Series. In section the ground- 
mass, which is much stained with red iron-oxide, is seen to be 
microcrystalline, and to show good fluxion-structure round the 
numerous phenocrysts of orthoclase. 
The large mass of rhyolite exposed at the point north-west of 
Owen also consists largely of a compact purple rock which shows 
neither banding nor nodules. This rock is very fine-grained, and 
almost uniformly cryptocrystalline. A fair number of phenocrysts 
of orthoclase, and also of albite, occur in it. Magnetite is fairly 
plentiful, occurring in minute patches thickly disseminated over 
small areas of the section, and also in larger grains. Sometimes 
xenoliths are present. 
The Fort-Dunore mass, the only important exposure of rhyolite 
occurring in the section along the west side of Smerwick Harbour, 
is a very compact fine-grained rock, showing no banding and only 
a few much-altered phenocrysts. 
(b) The Ashes. 
‘The number and variety of the ashes is very great. They 
vary in colour from white, through various shades of green, 
yellow, and grey, to purple, and in coarseness from extremely fine- 
grained and flinty rocks, to a rock the constituent fragments of which 
may reach a length of 2 feet. Some have the matrix silicified, and 
from this and other causes are often extremely hard to distinguish 
from rhyolites. Sometimes the best guide (as remarked by Mr. 
Harker) for discrimination between a rhyolite and a rhyolitic ash 
lies in the orientation of the felspars : in a rhyolite they tend to have 
a parallel arrangement, in an ash the arrangement is more irregular. 
One of the most noteworthy points with regard to the ashes, is that 
while the fragments sometimes resemble the local rhyolites, they 
are frequently of an andesitic nature, and often amygdaloidal, 
bearing no resemblance to any of the local rocks. 
The different types of ash may be grouped as follows :— 
(1) Very fine-grained pale ash.—The best example of this 
type of rock is band (A 23) exposed near the top of the cliff south- 
