Br Hibbert on the Distribution 
may be traced as far north as North Rheu and North aad 
South Holm, where it is associated with small masses of lime- 
stone. New strata, however, arise to the west of the chlorite- 
slate, consisting of mica-slate and gneiss, the southerly lateral 
edges of which meet the northerly bounding line of the granite 
at various angles. The strata of mica-slate are intercepted 
on the north by a mass of diallage-rock, occurring in the pe- 
ninsula of Fethaland. 
To the north of Fethaland, in the insulated rocks named 
Gruriie and the Ramnay Stacks, is found a conglomerate rock, 
consisting of ^anite, felspar and quartz, the relations of which 
are not evident. 
To the south-west of the granite is a considerable mass of 
claystone-porphyry, with a conglomerate and amygdaloidal rock 
,,of the same nature. The cavities of the latter are filled with 
, carbonate of lime, quartz-crystals and calcedony. This mass 
occupies a district, bounded on the south by a line drawn from 
Rraewick to Eshaness ; on the west, from Eshaness to the en- 
trance into Ronas Voe ; and on the east, by the large mass of 
•granite already described. 
THE SERPENTINE DISTRICT OF SHETLAND. 
The Gneiss of the Islands of Yell Sound, the large Island (f 
Yell, West of Unst, Sfc. 
Returning to the sienite of Yell Sound, we trace these strata 
from their junction with k, ;by their lateral edges, at the several 
islands of Yell Sound, named Brother Island, Little Rhooe and 
Samphray. Near' the junction of the gneiss with the sienite, 
the strata are much traversed by veins of hornblende. The 
whole of the Island of Yell is composed of gneiss, as well as 
the islands to the west. The strata are everywhere inters 
sected by small veins of granite, which, to the north-west of 
Yell, are almost as abundant as the strata which they traverse. 
The direction of the strata, disturbed much by these veins, may 
be stated at about N. 12° E. The dip is to the west, at 
^angles of about 45°. 
The northerly connexions of the strata are, for the most part, 
:€ut off by the sea. Some strata, however, may be identified io 
