6 HALF-HOURS IN THE GBEEN LANES. 



adhering to the legs and plumage of aquatic birds 

 from some distant river or lake, in which the birds 

 last revelled. Many of the plants may have been 

 transferred in a similar way, the wind bringing the 

 rest. Even in the formation and stocking of the 

 tarn, therefore, we cannot fail to observe the opera- 

 tion of purely natural laws, but they are none the 

 less indicative of providential care and direction. 

 Nature knows no sabbath her laws are ever at 

 work, but in their very operation declaring them- 

 selves but the visible operations of an active Deity. 

 How true are the words of the poet : 



"My heart is awed within me when I think 

 Of the great miracle which still goes on 

 In silence round me, the perpetual 

 Work of Thy creation. Finished, yet renewed 

 For ever!" 



As if a new world had been created, this little 

 tarn turns us to causes as powerful as the result, 

 in this instance, seems to have been small. The 

 geological phenomena which have resulted in the 

 depression of a small area, the physical agencies 

 which have filled it with water and turned it into a 

 miniature lake, the vital operations that have peopled 

 it, as though it were a new world are all worthy 

 the attention of the naturalist. 



Wherever the thick sheet of boulder-clay occurs 

 over chalk rocks, and some portion of the latter is dis- 

 solved away to form a " sand-pipe," there the clay will 

 be depressed and form a hollow. The water-holding 



