166 Proceedings of the Royal Physical Society. 



become extinct in Scotland, or are approaching extinction at 

 the present day. 



I have already pointed out the causes which I believe 

 brought about their decline or extinction. The circumstances 

 which have attended their increase present almost the con- 

 verse state of things. 



They have pressed forward in a general northerly direction 

 from all their various centres of restoration ; and I believe 

 this northward tendency in their advance is due to the com- 

 bined physical features of the country as explained above ; 

 ranges of mountains checking their advance south of the earlier 

 centres in the south of Scotland, and easier outlets being 

 found towards the north. As the wave gained impetus and 

 strength, obstacles which would, perhaps at first, seem insur- 

 mountable, became easier from the increasing inward pressure, 

 and even mountain passes of some altitude w^ere threaded, 

 and the first ripplings of the pioneer waves consequently 

 overflowed into the valleys beyond. We have proof that the 

 squirrel is not unfrequently found far away from wood, and 

 upon the open heaths. One was seen in 1830 on the moor 

 between Kenmore and Glenqueich, four miles away from 

 wood, as I am informed by Mr D. Dewar. Mr Dewar saw 

 one " about sixteen years ago, between Killin and Glenlyon, 

 half-way across, w^here there were ten miles of moor. It 

 was going north : when pursued it took to a hole." We have 

 also the anecdote related by Mr Knox, when a Highlander, 

 who had never seen a squirrel before, discovered one out upon 

 an open moor, and the animal, mistaking him for a tree, 

 mounted rapidly to the top of his head, to the no small fear 

 of the native, who believed it to be ''a thing wi' horns." * 

 Nor is it unusual to find squirrels down in the flat " carses "f 

 far from trees, having followed a road or a hedgerow perhaps 

 for miles. Eoads assist them ; for, as is well known, they 

 are fond of running along rides in forests, or rail tops ; and if 

 roads be made into a wild mountainous country, there can be 



* "Autumn on the SiDey," p. 51. 



+ "Carses," the name given to the rich level tracts of country below 

 Falkirk and Stirling and along the Tay— viz., Carse of Falkirk, Carse of 

 Stirling, and Carse of Goivrie. 



