98 THE EEPOKT OF THE Xo. 36 



that next the north the Austral Region, and the northernmost, the Boreal B|egion. 

 Naturally we are interested mainly in the last two of these areas. 



(Canada is, of course, largely within the Boreal Region, but the differences 

 within her territory are such that three sub-belts, called zones, are easily recogniz- 

 able. On the north, beyond the limit of the growth of trees, we find corresponding 

 changes in plant and animal life, establishing the Arctic Zone of the region. Here 

 are typically Arctic plants and such animals as the Arctic fox, polar bear, musk ox, 

 and ptarmigan. South of this, stretching across the continent .from Labrador to 

 Alaska, and southward along the tops of the Eocky Mountains i? the so-called 

 Hudsonian Zone. Its southern limit extends from near the mouth of the St. Law- 

 rence Eiver to the southern end of Hudson Bay, thence passes north- 

 west to near Great Slave Lake, then down the Mackenzie Eiver to 

 about 65 deg. latitude, after which, influenced by the mountainous heights, it 

 extends again to the south to about latitude 55 deg., sending narjow tongues farther 

 south along the mountain tops. As it approaches the western ocean, however, the 

 moderation of climate due to the Kuro sivo, or Japanese Gulf Stream, makes; its 

 influence felt, and the southern edge of the zone is driven north and is only able to 

 reach the western shore of the continent about five degrees farther north than it 

 was when the efi'ects of the ocean came within reach. As neither the Arctic nor 

 Hudsonian zones of the Boreal Eegiou iias great agricultural value, we now turn to 

 the third zone of this region — the Canadian — which with certain exceptions occupiea 

 the rest of the Dominion of Canada aud a portion of the United States. Here we 

 must look for the greatest agricultural returns and one of the best opportuniti^ 

 for the utilization of crops not as yet grown. 



The Austral Eegion occupies but a small portion of Canadian territory, but 

 what it does occupy is of great value, for here it should be possible to produce 

 crops not raised elsewhere in the Dominion, and to produce to perfection crops 

 only partially successful in the Canadian Zone. Like the Boreal, the Austral 

 Eegion is divided into three zones, the northern one being known as the Transition 

 Zone. How accurate our knowledge of the area occupied by this zone as shown on 

 the map is, may be questioned, but a strip around the Bay of Fundy and along the 

 shore of Lake Ontario, and the Southern parts of Manitoba, Saskatchewan, and 

 Alberta, besides the shore belt inthe region of Vancouver Island, are believed to 

 belong to this section. 



Next south comes the Upper Austral, and this appears to be present in Canada 

 only as a narrow strip along the shore of Lake Erie. How correct this is must 

 be determined by future investigation. 



It is a safe statement that Life Eegions and Zones are always limited by 

 barriers, though these may be of many kinds. Every kind of animal and plant has 

 an optimum temperature at which it thrives best. As we depart from localities 

 where this is true, and pass to the north, we will reach a latitude where it can no 

 longer exist, while if we pass to the south the same will hold. Sometimes the 

 limits will be established, not by temperature but by absence of food or by a change 

 from a moist to an arid climate or tlie reverse. A mountain chain of considerable 

 height may so affect temperature that forms reaching it are unable to cross and 

 enter a continuation of the same zone beyond. Near the shores of our continent 

 the infiuence of the ocean is a modifying factor, and others might also be enumei^- 

 ated, all affecting the arrangement of the regions. 



Evidence indicating the limits of these zones is gathered by a study of the 

 plants and animals present. Many plants found only a short distance south of the 

 international boundary disappear as we pass northward, and with them disappear 



