PEAT BOGS AND TURBARIES. 95 



winter montbs with fresh water ; and formed a lake of 

 considerable extent, havlng a small oiitlet into tlie sea at 

 the points, no doiibt where the rivers Parret, Brue, 

 and Axe, now dIscharge tlieir waters. In this way we 

 may readily conclude, the great barrier and ridge of sand 

 banks running from Brean Down to Burnhara and Hunt- 

 spill were formed, the river Brue belng the outlet on the 

 south-west at Highbridge, and the Axe of the district 

 lying at the foot of the Mendip ränge.* 



4. We find the former jestuary blocked up by the barrier 

 noticed above, converted into a lake, covering the extent 

 of district previously overflowed by the tide, though now 

 occasionally affected by its entering the level by the outlets 

 or rivers which carried off the flood waters. At thia 

 period, ^ve may presimie the labours of man commenced ; 

 when by sluices ei-ected at the mouths of rivers, and by 

 banks thrown up along their course, the influx of the tide 

 was prevented from inundating the low lands. In conse- 

 quence of these works, the lands becoming partially dry 

 in the summer, Vegetation soon began and spread rapidly 

 over the district, and was the origin of the rieh pastures 

 now to be seen in these situations. In the more morassy 

 parts, aquatic plants soon covered the waters, and became 

 the incipient ingredients in the formation of the Peat 

 bogs. 



It has been observed that no stream, whatever its size, 



* The foUowing observations made by Mr. De Luc, a foreign geologist 

 who visited England soine years since, are striking, and show the rapid 

 accumulation of alluvial marine deposits. " When," says he, " the tide 

 rises towards the coast, the whole moves together forward, and cxercises 

 its action on the bottom, agitating and raising the mud which it carries 

 towards the shoro, and there deposits it during the interval between the 

 flowing and ebbing of the tide ; but when the water retreats it flows back 

 from the surface only, beginning from the shorc, and exercising scarcely 

 any action on the bottom." — De Luc^s Travels in England, 



