230 REMARKS ON A FLOATING ISLAND. 



be found to rest upon a clayey, gravelly, or 

 even rocky substratum. In rainy seasons the 

 water from higher grounds being filtrated through 

 the more porous soil, insinuates itself underneath, 

 and not easily finding vent, raises up the lighter 

 stratum to a certain extent ; while the surround- 

 ing parts being of a less extensible nature, or 

 more strongly attached to the substratum, suffer 

 themselves to be overflowed. Of this kind seems 

 to be the floating island of Newbury-Port :* 

 but it appears rather extraordinary, that it should 

 be able to support '*six large trees,'* and yet 

 yield so considerably to the weight of a man. 



When a congeries of decayed vegetable matter 

 is deposited in a basin, formed in the earth, from 

 which the water has not sufficient drainage, the 

 lower parts are kept in a spongy state, while 

 the surface is compacted together by the roots 

 of growing vegetables. When, in a rainy season, 

 this spongy matter receives an additional supply 

 of water, it expands and bears up the superior 

 stratum ; while the circumjacent more solid parts 

 are overflowed. Of this kind I conceive are 

 some small islands, appearing in wet seasons, 

 in a meadow on the margin of Orasmere Lake. 



* Something of a similar nature are the bursts upon the 

 sides of mountains, where the peat earth rests upon a declivity 

 with dryer grounds above it. 



