194 NATURAL HISTORY 



mill. 11 Besides, most woodlands, forests, and chases, with us 

 abound with pools and morasses; no doubt for the reason 

 given above. 



To a thinking mind few phenomena are more strange than 

 the state of little ponds on the summits of chalk-hills, many of 

 which are never dry in the most trying droughts of summer. 

 On chalk-hills I say, because in many rocky and gravelly soils 

 springs usually break out pretty high on the sides of elevated 

 grounds and mountains; but no person acquainted with chalky 

 districts will allow that they ever saw springs in Such a soil 

 but in vallies and bottoms, since the waters of so pervious a 

 stratum as chalk all lie on one dead level, as well-diggers have 

 assured me again and again. 



Now we have many such little round ponds in this district ; 

 and one in particular on our sheep-down, three hundred feet 

 above my house ; which, though never above three feet deep 

 in the middle, and not more than thirty feet in diameter, and 

 containing perhaps not more than two or three hundred hogs- 

 heads of water, yet never is known to fail, though it affords 

 drink for three hundred or four hundred sheep, and for at 

 least twenty head of large cattle beside. This pond, it is true, 

 is over-hung with two moderate beeches*, that, doubtless, at 

 times afford it much supply : but then we have others as 

 small, that, without the aid of trees, and in spite of evapora- 

 tion from sun and wind, and perpetual consumption by cattle, 

 yet constantly maintain a moderate share of water, without 

 overflowing in the wettest seasons, as they would do if 

 supplied by springs. By my journal of May 1775, it appears 

 that " the small and even considerable ponds in the vales are 

 " now dried up, while the small ponds on the very tops of 

 "hills are but little affected." Can this difference be ac- 

 counted for from evaporation alone, which certainly is more 



11 Vide Kalm's Travels to North-America. 



* [One of the identical beeches here referred to was, for at least 50 or 

 60 years, leaning at a considerable angle over the pond, and has fallen 

 prone into the water only very recently. It was not a large tree j it had 

 become somewhat decayed, but retained its leafy head until it fell up- 

 rooted. T. B.] 



