50 Proceedings of Royal Society of Edinburgh. [sess. 
inferior mass, did reappear a few miles to the east of Inveraray, 
upon the same northern shore of Loch Fyne, and to this bed 
accordingly my first search was directed. That search led me at first 
into a mistake as to certain appearances — a mistake not without 
instruction on the danger of preconceptions in the interpretation of 
obscure phenomena. I found on the surface, and apparently 
embedded in the grain of the stone, certain ramifying filaments and 
minute tubes in red oxide of iron, together with certain knots which 
seemed at first sight to be the seed capsules of some plant. On 
breaking up the rock I found interspersed throughout its substance 
certain discoloured spots, which almost invariably took the form of 
ovate or spatulate rings, all more or less like the form of a battledore, 
but without any appearance of a stalk or handle to the battledore. 
Connecting these internal oval rings with the external forms of 
vegetable structure preserved in casts of red oxide of iron, I was 
inclined to believe that they were the same in origin, and that the 
more distinct character of the forms on the surface was due to that 
effect of weathering which so often reveals organic remains upon 
the surface of rocks when no such forms can be detected in the 
fresh fracture. In pursuit of this idea, I had the rock opened 
and split at various points of the outcrop of the beds ; and every- 
where I found, sometimes thickly interspersed, sometimes thinly 
scattered, oval stains and spots, and some lines, which were all 
apparently referable to the same ultimate cause and source, whatever 
that might be. At one place these small ovate stains passed out of 
the quartzite altogether, and were repeated in some finely laminated 
overlying beds of pure micaceous schist. This, however, occurred 
only where such schists lay in immediate contact with the quartzite 
— an observation which is important, because the total absence of 
them in the great masses of overlying schists and schistose com- 
binations which constitute the bulk of our hills, is one of the 
features in the case. The occurrence of the oval rings and other 
discoloured impressions, which forms the subject of this paper, is, 
so far as I have yet seen, strictly confined to the quartzite beds, and 
to a few inches of very fissile mica slate which lies in immediate 
contact with that rock. 
Two specimens, or sets of specimens, and these alone, contributed 
for some little time longer to carry on my impression that they 
