SILTING UP OF THE CREEKS OF FALMOUTH HAVEN. 13 



That this mischief has been considerable is evident, and in 

 order to ascertain its extent, I have consulted the whole of the 

 available printed maps and charts, and many others in manu- 

 script, at the British Museum, which could give any information 

 with reference to the subject. The three earliest charts giving 

 soundings are a Survey of Falmouth Harbour made in 1597, by 

 Baptista Boazio,* Captain Grenville Collin's chart in Great 

 Britain's Coasting Pilot, published in 1681, and another M.S. 

 chart, drawn by Edward Dummer for the Admiralty in 1698, 

 and these three maps are those mainly used in the following 

 statement. 



The silting up of the Fal below Tregony bridge is clearly 

 shown by a comparison of the Admiralty Chart of 1855, with the 

 one drawn in 1698 by Edward Dummer for the Lords of the 

 Admiralty. Opposite Ardevora, where there was in 1698 six feet 

 of water at low water spring tides, was in 1855 a bank reaching 

 a foot above it, being 7 feet accumulation. At Tolvern Point 

 where there was 24 feet of water in 1698, there was in 1855 but 

 12 feet being 12 feet less ; and Tregothan boathouse with formerly 

 30 feet, in 1855 had but 12 feet, showing 18 feet of deposit to 

 have accumulated at this spot. 



It is thus very apparent that serious shoaling is going on 

 below Puan, and that the recession of the tide that I traced at 

 our last meeting, from Tregony downwards, still continues in 

 the tidal reaches of the Fal. 



Tresilian Creek is the next branch of the Haven of any extent. 

 The watershed above Tresillian Bridge is 13,820 acres, and the 

 average discharge of the stream will be about 2200 cubic feet 

 per minute. Turning now to the early maps before referred to, 

 that of Baptista Boazio, in 1597, shows but little mud bank as 

 then existing below S. Clements Point, and at this spot Cajotain 

 Collins shows 3 feet at low water in the channel, where now the 

 bottom is a foot above, being four feet accumulation. 



There is but little Mineral or China Clay water now flowing 

 into this creek carrying silt, although formerly stream tin 

 works existed above Ladock, and the deposit of the extensive 

 mud banks is mainly alluvial. 



* For this most valuable map I am indebted to the courtesy of Mr. W. H. 

 Tregellas. 



