380 THE FOSSILIFEROUS 
zoophytology the late lamented Dr. Landsborough has ac- 
knowledged in his interesting “ History of British Zodphytes.” 
Further, it is worthy of remark that, just as the naturalist can- 
not now acquaint himself with all the animals or plants of 
Scotland in any single locality, so all the fossil species of any 
one formation cannot be exhausted in any one limited field or 
district, but must be sought for in various districts ere the list 
can be regarded as tolerably complete. The old Devonian spe- 
cies of fishes, like those of the present day, seem to have had 
their favorite haunts and feeding or spawning grounds, and 
must now be sought for where they congregated of old. The 
Diplacanthus striatus, for instance, is one of the commonest of 
the Cromarty Old Red fishes, and the Dipterus and Asterolepis 
very rare; whereas at Thurso, Mr. Dick, after years of explo- 
ration, never found a single spine of Diplacanthus, but not a 
few noble specimens of Asterolepis, and finely preserved skulls 
and jaws of Dipterus. And in a neigboring locality, Bannis- 
kirk, Dipterus is the prevailing fish, and may be found by 
scores. Again, the Old Red of Caithness generally is poor in 
specimens of Pterichthys,— the rocks of Thurso have not yet 
furnished a single specimen; whereas in those of Moray the 
genus is not rare; and in a quarry a few miles to the north- 
east of Stromness it is more abundant than any of its contem- 
poraries. I mention these facts to show how necessary it is to 
the Palzontologist who sets himself to exhaust the organisms 
of a formation within even a single country, that he should 
either be a sedulous traveller, or have a widely-located circle 
of friends engaged with him as fellow-laborers in the work. 
No ichthyic species of this Lower formation of the old Red 
Sandstone has yet been detected in Scotland to the south of the 
Grampians. In the great belt of Old Red which traverses the 
island diagonally, from the coasts of Kincardine and Forfar- 
shire on the east, to those of Renfrew and Ayr on the west, 
