52 Proceedings of Boyal Society of Edinburgh. [sess. 
Eeference was also made to the Great Bustard {Otis tarda) and to 
the Great Auk {Alca impennis) in connection with other subjects 
discussed in the paper. In conclusion, it was held that an adequate 
description of the environments, physical and vital, of the mammals 
and birds earliest recorded by Scottish observers would shed much 
light (1) on the physical features of the districts frequented by them 
at the time of their first record ] (2) on the climatal condition of these 
districts ; (3) on their fauna and flora ; (4) on the value of the biotic 
element in schemes of classification of Surface Deposits ; (5) on the 
phenomena of migration; (6) on the laws and the limits of variation; 
and (7) on some questions of ancestral history. Many of the materials 
for generalisation on these questions lie often at present in out-of- 
the-way records, and, to most, in recondite quarters, but they are 
worth being sought for and utilised as a branch of common culture, 
and, chiefly, as a great help to writers of civil history — help which 
can be given only by students in the departments to which reference 
has been made. 
