1898.] 



on a Yorlishire Moor, 



625 



its growth it is likely to be particularly wet. Sphagnum often 

 spreads over the surface of i)ools or even small lakes, not nearly so 

 often in Yorkshire, however, as in a country of well glaciated 

 crystalline rocks, where lakes abound. In such cases a peculiar 

 kind of peat is formed as a sediment at the bottom of the water, 

 which may in the end fill u]) the hollow altogether. A very slight 

 cause is enough to start a Sphagnum bog, such as a tree falling 

 across a stream, or a beaver dam. When a pool forms above the 

 dam, the Sphagnum spreads into it, and the peat begins to grow. 

 Long afterwards, when the hollow is 

 completely filled with peat, there may 

 be a chance for grasses, rushes, crow- 

 berry and heather. 



In our own time and country the 

 moors waste faster than they form ; it 

 is much commoner to find the grass 

 gaining on the heather than to find the 

 heather gaining on the grass. There 

 is no feature of the Yorkshire hills 

 more desolate than ground coveied with 

 wasting peat. The surface is cut up 

 by innumerable channels, with peaty 

 mounds between. These are either 

 absolutely bare, or thinly covered with 

 brown grasses and sedges. The dark 

 pools which lie here and there on the 

 flats are overhung by wasting edges of 

 black peat. It is cheerful to step from 

 this dismal territory to ground clothed 

 with close-growing grasses of a lively 

 green, such as we find where the peat 

 has disappeared altogether. 



The moors are commonly wet, very 

 wet in places. In certain parts and 

 during certain seasons of the year they 

 are, however, particularly dry, and 



V 



Fig. 8. — Ling (Calhrna vulga^ 

 ris). A leafy branch ; a single 

 leaf, seen from beneath ; and 

 a cross section of the base of 

 the leaf. 



subject to a severity of drought which 



the lower slopes and the floor of the valley know nothing of. At 

 lower levels trees give shelter from sun and wind ; night-mists check 

 evaporation, and even return a little moisture to the earth ; the deep, 

 finely divided soil lodges water, which is given off little by little, and 

 in our climate never fails to yield an effective supply to the roots ; 

 pools and streams dole out sparingly the Mater which fell lon^z before 

 as rain. But the moor lies fully open to sun and wind. In iMarcli it 

 is exposed to the east wind ; in June to hot sun and cold, clear nights ; 

 in August there is perhaps a long spell of drought ; in November 

 heavy gales with abundance of rain. Tiie summer is late ; the moor- 

 land grasses make little growth before the bcginnins; of June; even 



