WILD LIFE IN A SOUTHERN COUNTY. 73 



the earth. These tiny shells have had millions of 

 ancestors : Nature seems never weary of repeating 

 the same model. 



In the osier-bed the brook-sparrow chatters ; there, 

 too, the first pollard willow stands, or rather leans, 

 hollow and aged, across the water. This tree is the 

 outpost of a thousand others that line the banks of 

 the stream for mile after mile yonder down in the val- 

 ley. How quickly this little fountain grows into a 

 streamlet, and then to a considerable brook, with- 

 out apparently receiving the waters of any feeders ! 

 In the first half-mile it swells sufficiently, if bayed up 

 properly, to drive a mill as, indeed, many of the 

 springs issuing from these coombes do just below the 

 mouth. In little more than a mile, measuring by its 

 windings, it becomes broad enough to require some 

 effort to leap it, and then deepens into a fair-sized 

 brook. 



The rapidity of the increase is accounted for by the 

 fact that every field it passes whose surface inclines 

 towards it is a water-shed from which an unseen but 

 considerable drainage takes place. When no brook 

 passes through the fields, the water stands and soaks 

 downwards, or evaporates slowly : directly a ditch 

 is opened it fills, and the effect of a stream is not only 

 to collect water till then unseen, but to preserve it 

 from evaporation or disappearance into the subsoil. 

 Probably, if it were possible to start an artificial stream 

 in many places, after a while it would almost keep it- 

 self going at times, provided,, of course, that the bot- 



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