==Fauna== The three climatic regions of Alberta have naturally a varying fauna.
For example, rae Arenarion in one climatic or geographical region might be in~~ med an a-Arenarion and one in a different region a a-Arena- ~j1j ri, and so on (Moss, bc. cit.).
Finally, within any district of constant or fairly constant climatic conditions, it is possible to distinguish plant communities which are related chiefly to edaphic or soil conditions; and the vegetation units of these definite edaphic areas are the plant formations of some writers, and, in part, the edaphic formations of Schimper.
The evidence which has thus been briefly summarized, points unmistakably to the conclusion that existing vegetation originated in the northern hemisphere and under climatic conditions corresponding to what would now be termed sub-tropical.
Of this line it is customary to distinguish several zones, lying, generally, parallel to it, and, differentiated chiefly by climatic differences.