A. Giekie— Crystalline Rocks of the Scottish Highlands. 13 
ful mill has acquired a new schistosity parallel with the shearing- 
_ planes. Hornblende-rock has been converted into hornblende- 
schist. Moreover, new minerals have likewise made their 
appearance along the new divisional planes, and in many cases 
their longer axes are ranged in the same dominant direction 
from east-southeast to west northwest. 
been in great measure effaced, lenticular bands occur in them 
which can certainly be recognized. Some of these bands are 
unquestionably parts of the Archean gneiss; others are Silurian 
uartzite, and in one case we can detect a large mass of the 
per Durness limestone. Traced eastward, however, the 
crystalline characters become more and more pronounced until 
limestone and calcareous schist, which has been traced for many 
miles above the great thrust-plane, certainly suggests that it 
represents the upper part of the calcareous Durness series 
attenuated and altered by the intense shearing which all the 
rocks have undergone. ‘This much at least is certain, that the 
Schistose series above the thrust-plane is partly made up of 
Silurian strata, and has received its present dip and foliation 
since Silurian time. . 
7 aving satisfied myself that Murchison’s explanation of the 
order of sequence could not be established in Eriboll, I was 
