XI. CLIMATAL ZONES. 485 



100 200 300 400 500 600 yards on a mountain in lati- 

 tude 58, — and should then find a and / ceasing respec- 

 tively in 60 and 70 of boreal latitude, it would still be by 

 no means certain that b c cl e would be found to cease 

 at the corresponding intermediate latitudes of 62 64 66 

 68. Something similar might be expected, and would 

 frequently be found ; but the same succession would not 

 occur either equally or constantl3^ 



It will be recollected that two primary divisions were 

 adopted in the first volume, pages 32 and 33, for the basis 

 of a climatal arrangement in this country. — 1. The agi'a- 

 rian region included the whole coast-level and low grounds, 

 up to the limit of cultivation ; rising some hundreds of 

 feet. higher in South Britain than in North Britain. — 

 2. The arctic region included the acclivities and summits 

 of the mountains above the limit of cultivation ; com- 

 mencing some hundreds of feet higher in the South than 

 in the North, and at a very slight altitude in the extreme 

 North, as in Shetland. These two regions were sub- 

 divided each into three subordinate zones (vol. 1, page 40) 

 thus : — 



6. Super-arctic zone. 8. Super-agrarian zone. 



5. Mid-arctic „ . 2. Mid-agrarian „ 



4. Infer-arctic „ 1. Infer-agrarian „ 



The three agrarian zones are chiefly latitudinal, while the 

 three arctic zones are exclusively altitudinal in this 

 country. On passing to more northern lands the latter 

 become latitudinal ; while in passing southward from 

 Scotland into England the upper agi-arian zone is found 

 above the middle one ; and on reaching Wales, both mid- 

 dle and upper have place above the lower ; so that the 

 three agrarian zones also become altitudinal there. The 

 descending levels of the zones, as traced from south to 

 north, are indicated by the oblique lines which separate 



