Geological Society of London. 327 
the following classification of the quartzo-dolomitic series, which, in 
the absence of clear proof of its age, he called the ‘‘ Assynt Group,” 
the subdivisions being taken in ascending order :— 
C,. Torridon Sandstone and Ben More Grit. 
C,. Quartzite. 
C, 1. Seamy. C, u. Annelidian. 
C;. Brown Flags. 
C,. Salterella Grit and Quartzite. 
C,. Dolomite. 
C,; 1. Dark. C, u. White. 
For the eastern gneiss the author proposed the term ‘ Caledonian.” 
Taking the country examined from south to north, Loch Broom was 
first described. Here the author considered there was clear proof of 
dislocation. Between the Torridon and the Caledonian there were 
several subparallel faults, which increased in throw from west to east, 
Torridon Sandstone being first brought up through the quartzite, then 
further east through the dolomite, while still further east the Hebridean 
was thrown up, the Caledonian appearing east of the Hebridean. This 
Hebridean was the ‘porphyry ”’ of Nicol. 
In Assynt the ‘‘ Upper Quartzite” was first discussed. The author 
described several sections which he considered to prove that this band 
was the ordinary quartzite repeated east of a great fault, which brought 
up the Hebridean ; in one place, Glen Coul, the quartzite being con- 
formably succeeded by the brown flags and dolomite. 
The ‘‘igneous rocks”? of Nicol (‘‘ Logan Rock” of Dr. Heddle) 
were regarded as the old gneiss brought up by a fault and thrown over 
on to the Assynt group to the maximum breadth of more than a mile. 
The ‘‘ Upper Limestone’”’ of authors was described as either outliers 
_. of the dolomite or a part of the Caledonian series. 
The Caledonian rocks were seen in Glen Coul to be immediately 
overlying the Hebridean, the Assynt group being caught in the angle 
between the two gneisses, and bent back in overthrown folds. 
The mountain groups of Assynt were described as usually consisting 
of cores of Hebridean gneiss swathed in or capped by sheets of quart- 
zite. In the former case the quartzite on the western slopes was 
contorted into overthrown folds by the thrust from the east. 
In the Loch-Erriboll district, the ‘‘ granulite” of Nicol was considered 
to be a lower division of the Caledonian gneiss, though bearing some 
resemblances to the Hebridean. In other respects, the views of Nicol 
were regarded as substantially correct. Along the entire length of 
Loch Erriboll, a distance of about twelve miles, the thrust from the 
east had bent back the Assynt group into overthrown folds, and pushed 
the Caledonian gneiss on to the top of the inverted quartzite. This 
had produced the appearance of an “‘ upper” quartzite passing ‘‘ con- 
formably ” below the eastern gneiss. The superior antiquity of the 
Caledonian was confirmed by the occurrence of outhers of quartzite 
upon the Arnaboll (Lower Caledonian) series, and by the fact that the 
granite, which sent numberless veins into the gneiss, never penetrated 
the quartzite and associated rocks. 
2. “On a Group of Minerals from Lilleshall, Salop.” By C. J. 
Woodward, Esq., B.Sc., F.G.S. 
