190 GEOGKOSTICAI. SKETCH OF THE 
XVI. — Geognostlcal Sketch of Part of the G?rat 
Glen of Scotland, 
By Mr George Anderson of Inverness. 
(Read l^th January 
In this communication I propose to give a mineralogical 
sketch of part of the Great Glen of Scotland. 
This extensive valley cuts across the Island in the direc- 
tion of NE. and SW. from Inverness to Fort William, and 
thereby forms the boundary between the middle and north- 
ern divisions of Scotland. Its bosom is adorned and en- 
riched by the Lochs Ness, Oich, and Lochy ; and the al- 
luvial depositions that cover its surface constitute the bed 
of the Caledonian Canal. Its utmost length, from sea to 
sea, may be about 62 miles ; and although Inverness marks 
its termination on the eastern coast, still the ranges of 
mountains that bound its sides do not stop exactly at that 
point, but run on for several miles, on both sides of the 
Murray Frith. 
As the geological description of these mountains forms 
a principal object in the present communication, we shall 
