ON THE 
RED SANDSTONE, MARBLE, AND QUARTZ 
DEPOSITS OF ASSYNT; 
WITH THEIR SUPPOSED ORGANISMS AND PROBABLE 
ANALOGUES. 
In hurriedly journeying, two years ago, through the upper 
parts of Assynt, on my way to Loch Inver, I was so struck by 
the appearance of the stratified limestone deposit to which 
the marble beds of that locality belong, that I returned last 
season to examine it more at my leisure, and to trace, if possi- 
ble, its relations to the other rocks of the country. I had been 
impressed, in the passing, both by its peculiar aspect, and its 
occurrence in the same wild tract with a remarkable system of 
sandstone mountains, unique in the British islands, which have 
been represented by M‘Culloch as formed of the Old Red 
Sandstone, and which, from the nearly horizontal disposition 
of their strata, he regarded as hills of denudation. It is impos- 
sible, he argued, carefully to examine these widely-separated 
mountains, formed of thin nearly horizontal beds of ripple- 
marked sandstone, that rest unconformably on the fundamental 
gneiss of the district, without coming to the conclusion that 
they are but the mere fragments of a once continuous sandstone 
bed, from one to three thousand feet in thickness, of which by 
