INTRODUCTORY EXPLANATIONS. 5 



between 900 and 1800 feet. The average annual temperature 

 may be estimated at 42° to 45°. Its upper limit is marked 

 botanically by the cessation of Pteris, Digitalis, Erica, 

 Parnassia, and Pingiticula. Above it there are no trees, 

 either wild or planted, except a few isolated rowans and junipers 

 on the high crags. A great many of the mountain tarns fall 

 within the boundaries of this zone. At the Lakes there is 

 scarcely any arable cultivation above the Mid-agrarian zone, 

 and there are very few houses at a higher level. The notion 

 that the little inn at the top of Kirkstone Pass, which is the 

 highest regularly inhabited house in the Lake district, is also 

 the highest inhabited house in the whole of England, is a 

 local myth which is destitute of true foundation. It stands 

 at a little under 1500 feet above sea-level, and there are many 

 scattered farm-houses on the Pennine chain in Yorkshire, 

 Durham, and Northumberland at from 1800 to 2000 feet. 

 In Allendale there is a village of considerable size called 

 Coal Clough, which stands at from 1650 to 1700 feet in eleva- 

 tion. One of the principal characteristics of the Lake 

 district, from our present point of view, is that here, broadly 

 speaking, cultivation does not reach up to the top of the 

 Super-agrarian, but only to the top of the Mid-agrarian zone, 

 and that consequently at the Lakes the highest localities of a 

 crowd of plants that follow in the footsteps of man are a whole 

 zone, or half a zone, below their proper climatic limits, and 

 the Super-agrarian flora at the Lakes is materially smaller than 

 in the eastern counties. 



Zone 3 — Watson's Infer-arctic zone — includes a mountain 

 belt between 1800 and 2700 feet in altitude, with an average 

 temperature of 39° to 42°. Only the two highest tarns, Red 

 Tarn on Helvellyn, and Sprinkling Tarn on the north of 

 Scawfell, fall distinctly within the bounds of this zone. The 

 rest is bare hill and slate crag, where the Alpine plants, such 

 as Oxyriareniformis, Silene acaulis, Sedum Rhodiola, Saxifraga 

 oppositifolia, Saxifraga nivalis, Cerastium alpinum, Hieracium 



