THE OLD RED SANDSTONE. 119 
researches, and traced the formation in ravines and the beds 
of rivers, from the village of Buckie to near the field of Cul- 
loden; he found it exposed in the banks of the Nairn, in the 
ravines above Cawdor Castle, on the eastern side of the hill 
of Rait, at Clune, Lethenbar, and in the vale of Rothes— 
and in every instance low in the Old Red Sandstone. The 
formation hitherto deemed so barren in remains proved one 
of the richest of them all, if not in tribes and families, at 
least in individual fossils; and the reader may form some 
idea of the extent in which it has already been proved fossil- 
iferous, when he remembers that the tract includes as its ex- 
tremes Orkney, Gamrie, and the north-eastern gorge of the 
great Caledonian Valley. The ichthyolites were discovered 
in the latter locality in the quarry of Inches, three miles be- 
yond Inverness, by Mr. George Anderson, the gentleman to 
whose geological attainments, as one of the authors of the 
Guide Book, I have lately had occasion to refer. 
I had now corresponded for several years with a little circle 
of geological friends, and had described in my letters, and in 
some instances had attempted to figure in them, my newly- 
found fossils. A letter which I wrote early in 1838 to Dr. 
Malcolmson, then at Paris, and which contained a rude draw- 
ing of the Pterichthys, was submitted to Agassiz, and the 
curiosity of the naturalist was excited. He examined the 
figure, rather, however, with interest than surprise, and read 
the accompanying description, not in the least inclined to 
scepticism by the singularity of its details. He had looked 
on too many wonders of a similar cast to believe that he had 
exhausted them, or to evince any astonishment that Geology 
should be found to contain one wonder more. Some months 
after, I sent a restored drawing of the same fossil to the Elgin 
Scientific Society. I must state, however, that the restora- 
