THE RIVER MERSEY. j33 



removal of the Light-vessel about 2000 yards north-westwardly of its position 

 in 1846; the diminution of its average depth from 30 feet to 29 feet; and 

 the diminution of its average area from ISjS^O yards to 17,500 yards. 



The direction of this portion of the channel had been slightly altered, as 

 indicated by the change in the position of the Light- vessel. 



In that portion of this channel between the two Light-vessels, the changes 

 had consisted of the removal of the Formby Light-vessel about 750 yards 

 north-westwardly; an increase of the average depth from 26 feet, in 1846, 

 to 28 feet in 1852; and a diminution of the average area from 18,600 yards, 

 in 1845, to 16,450 yards in 1852. 



In its whole length, the Crosby Channel during this period had been 

 elongated about 500 yards ; its average area diminished from 18,443 yards to 

 17,126 yards; and its average depth nearly stationary, but slightly increased. 



The change in the position of the Crosby Light-vessel appears to have been 

 occasioned by the growth of a large elbow upon Great Burbo. The Formby 

 vessel appears to have been moved partly for the same reason, and partly 

 from a change in the position of Little Burbo, on the northern side of the 

 Victoria Channel. 



Victoria Channel. — The position of this channel had again undergone 

 very great change, the Bell Buoy having been removed about 1000 yards to 

 the southward, or nearly midway between its positions in 1840 and 1837. 

 The average depth of water on the bar had been very much the same in 

 1852 as in 1849, that is, rather less than in 1846. 



Zebra Channel. — The minimum depth of water in this channel had 

 increased from 6 feet, in 1846, to 7 feet in 1852; in other respects it had 

 remained without material alteration. 



Formby Bank. — This bank had been enlarged by the accession of the 

 Jordan Bank, and by its OM'n increased elevation : in 1846 the volume of 

 Formby Bank was nearly 13,000,000 yards; and that of Jordan Bank 

 1,500,000 yards, making a total of 14,500,000 yards ; in 1852 these quantities 

 were respectively 1 1 ,000,000 yards and 4,750,000 yards, or a total of 1 5,750,000 

 yards. Its position had been stationary. 



Mad Wharf. — This bank had sustained a slight loss of elevation ; but this 

 had been compensated in volume by an extension westward, the entire con- 

 tents having been nearly 6,500,000 yards in 1852, against nearly 5,750,000 

 yards in 1846, the former quantity being very nearly identical with that of the 

 same bank in 1840. 



Taylor Bank. — Taylor Bank and Jordan Flats, the former of which in 

 1833 had no existence, and the latter at that date of very minor importance, 

 had not only united in 1849, but in 1852 had largely increased in volume; 

 and in the same period had moved into close proximity with the united 

 Formby and Jordan Banks. During the period since 1833, Little Burbo, the 

 Middle, the West Middle, and other outlying banks had either been depressed 

 below low-water level, or had disappeared altogether. 



Great Burbo. — This bank had undergone material alterations since I846j 

 one of which was the extraordinary growth of the north-east angle in Crosby 

 Channel before-mentioned ; other important changes of outline may be 

 noticed on inspection of the cliarts ; perhaps the most remarkable alteration 

 is the increase of bulk, arising partially from enlarged area, but principally 

 from increased elevation ; and it is to be observed that this additional eleva- 

 tion is generally diffused over the whole bank. In 1846 the volume of this 

 bank had been calculated to be about 59,750,000 yards; in 1852 it had in- 

 creased to 69,500,000 yards. 



Western Channel. — In 1852 the Rock Channel had again undergone a 

 1856. D 



