314 Dr Hibbert on the Rochs (^Shetland, 
The clay-slate is either immediately connected with the sandi 
stone, or is separated from it by the interposed strata which 
have been described as for the most part lying beneath the con- 
glomerate rock. At Sandlodge there is interposed, for instance, 
quartz containing innumerable small veins of calcareous-span, 
also some little serpentine, talc and chlorite-slate : At Uker- 
setter, much quartz and limestone ; to the north of Fladabister 
a striated mica-slate ; at Quarf, thin beds of mica-slate, and gneiss 
with granite ; at Rovie Head, stratified quartz and limestone. 
An alternation of the clay-slate with the granular quartz or 
sandstone, and a graduation into it, is observed on the shore near 
Grimmister, which appearance, in reference to a date of forma- 
tion, assigns that sandstone, which is not characterised by the 
admission of rounded pebbles, to a place in our systems, where it 
can be associated with rocks usually supposed to be of the 
oldest kind. 
Near the junction of the clay-slate at Sandlodge, and in that 
sandstone which consists altogether of granular quartz, some 
copper mines were, a few years ago, wrought. The profits 
arising were too small to justify a continuance of the operations. 
As the shafts are now so much filled with w^ater, as to exclude any 
observation of the contents of the bed, the best information is to 
be found in Dr Traill’s account, as inserted in the Appendix to 
Mr Neill’s Tour *. The direction of the bed is from north-east 
to south-west. The copper-ores found were, 1. Friable and 
amorphous carbonate of copper, colour rich green. 2. Carbo- 
nate of an emerald green, crystallized in capillary fibres of a 
silky lustre, diverging in radii from a centre. This was 
found imbedded in iron-ore. 3. Sulphuret of copper dissemi- 
nated through felspar in some places, and in others in gi'eat 
masses of iron-ore. The iron-ore was, 1. Dark brown, fibrous 
and mamillated haematites. S. Columnar bog-iron-ore. 3. 
Micaceous iron-ore. 4. Brown iron-ochre. 5. Dark brown sta- 
lactitic iron-ore. 6. Earthy matter charged with iron, arising 
from the debris of other ores. 
( To he concluded in our next Number. ) 
* Appendix to Neill’s Tour through Orkney and Shetland, P^ge ITO. 
