THE RIVER MERSEY. 3? 



the western channel at its junction witli the river will also tend to weaken 

 the scour of the water when the tide is low. 



It appears f.jien that the freshes of 1852, in passing down the northern 

 channel, were deflected by the banit called Taylor's Bank and Jordan Flats, 

 on to the N.E. elbow of Great Burbo, itself of recent formation ; after 

 passing that elbow the ebb took the direction due to the impetus down 

 Crosby Channel, moditied by the influence of Taylor-Jordan Bank combined 

 with Great Burbo, passed over the shoals between the Zebra and Victoria 

 Channels, and opened up the svvatchway now known as the Queen's Channel. 

 The channel thus initiated by the freshes of 1852 was deepened by the con- 

 tinued action of the ebb tide throughout that year and the following, until 

 in 1854 we find the Queen's Channel formed, the Zebra silting up from the 

 loss of the water which then passed by the new channel. On the Victoria 

 Bar, again, these freshes had won a slightly increased depth of water. 



The contraction of the Rock Channel may be due to the drift of sand 

 promoted by the N.W. wind. 



The most remarkable gales of the period 1852 and 1854 are those of De- 

 cember 25 and 27, 1852, from the W.S.W. and S.W., from denudation by 

 which the Cheshire land would protect the sand-banks; February 26, 1853, 

 from N.N.W. ; January 26, 1854, from W.; and February 17 and 18 of the 

 same year, fi-oni N.W. and W.N.W. 



Very important changes have been recorded as having taken place between 

 the years 1846 and 1852. They may be briefly described as consisting of 

 the enlargement and consolidation of all the banks, with the bare exception 

 of Mad Wharf, the increased size being in great measure due to increased 

 elevation; the elongation of the Crosby Channel, chiefly in that part between 

 the Rock Light and the Crosby Light-vessel ; and the diminution of the 

 average depth and area of this portion of the channel, accompanied by a 

 slight alteration in its direction ; in that part of this channel, between the 

 Crosby and Formby Light-vessels, the depth was considerably increased, but 

 the area diminished ; the changes in the channel were occasioned by the 

 growth of the north-east elbow of Great Burbo, and an accretion on the 

 western side of the Taylor-Jordan Bank, both of which had taken place 

 principally after the 1849 survey. 



On reference to the Warrington tables, we find that, in 1846, the rain-fall 

 was slightly, but very slightly, below the average of twelve years ; in the 

 three following years it was above the same average, particularly in 1847> 

 when the excess was about 16 per cent. ; in 1850 the fall was 10 per cent, 

 below the average, and in 1851 slightly above. It appears then, that during 

 the years 1848 and 1849, and particularly in 1850, the banks had grown in 

 directions to produce, in 1851, those changes which rendered necessary the 

 survey of 1852. The increased depth of the channel between the lightships 

 above mentioned, seems due to the contracted width of that part, consequent 

 upon the enlargement of the banks. 



We have no record of the phsenomena of wind during this period, and 

 therefore can only conjecture that the horizontal and vertical growth of the 

 banks are effects to which the prevailing winds may have been accessory, 

 assisted by the loss of scour caused by the extensive dock-works of Liver- 

 pool and liirkenhead. 



The change in the positions of the light-vessels and of the Bell Buoy was 

 made after 1849. The depth of water on the Victoria Bar remained sta- 

 tionary. 



In the Zebra Channel the depth of water had increased between 1846 and 

 1849, when the rain-fall was rather above the average; and between 1849 

 and 1852 the depth had diminished again. 



