50 THE SBVEEN TUNNEL. 



and will presently show — with very large quantities of solid 

 matters, varying in size from a large and coarse gravel 

 downwards to fine gravel, sand, and mud — dne, no doubt, to 

 the groat rise and fall of the tides in this river, which 

 amount sometimes to fifty vertical feet in one tide, and to 

 the powerful currents thereby generated. 



The portion of the river Severn near the Kow Passage 

 Ferry is very remarkable because of these half-tide rooks, 

 which end abruptly at the Ferry channel, in a lino nearly 

 square across the river. These rocks, called on the English 

 sido the " English Stones," reach all tlu; wiiy across the 

 river, with the exception of the Shoots channel ; and their 

 abrupt ending is one cause of the existence of a Ferry 

 channel, the other being the peculiar sot of tlio tidal cui'- 

 rents there. They are also the reason why all the Severn 

 water helow half-tide level has to pass through the Shoots 

 channel, which is only 400 yards wide ; for there is then no 

 other outlet. 



All these waters rushing down this narrow channel of the 

 Shoots, naturally cause a very powerful current (ten knots an 

 hour, sometimes), which, no doubt gave this channel its name. 

 Again, the Shoots channel, as yon ascend the river, points 

 towards the Welsh shore, so that tlie in-flomng tide presses 

 against the Welsh shore ; while on, tlicj otliei' hand, the main 

 stream of the ehUng tide is flung towards the English shore 

 by the projecting point of St. Tecla's Chapel Eock, thus 

 leaving an interraediato sandbank, called the Dun Sand, in 

 the middle of the river, between the up and the down cur- 

 rents. The ebbing tide, thus thrown on to the English side, 

 passes over the English Stones so long as the tide is high; 

 but as half-tide is approached, the waters, having no longer 

 an outlet that way, rush along the head of the Ihiglish 

 Stones down to the Shoots, and thus have to cut through the 



J 



