THE BIVER MERSEY. 41 



fined to a small lineal extent of the coast, about two miles. The situation is 

 one that is now very much exposed to the flood tide through the Horse Chan- 

 nel, especially in N.W. winds. The geological formation is entirely alluvial, 

 consisting of sand, peat, and clay. It is, in fact, the site of part of the so- 

 called suijuiarine forest of Wirral. 



When Hoyle Lake was in existence, the flood tide advancing in two 

 streams — one through the lake, the other through the Horse Channel — met 

 at this place, and their united stream ran up the Rock Channel. It may be 

 assumed that the influence on the beach of the stream through the Horse 

 Channel was mitigated by the stream through Hoyle Lake, by which it 

 was deflected into the Rock Channel. As the lake was silted up the influ- 

 ence of the stream was gradually weakened, until it was entirely lost by the 

 closing up of the lake. The enlargement of the west spit of Great Burbo 

 has also assisted to give to the stream through the Horse Channel, a more 

 direct set upon the beach. About thirty years ago the late Mr. Giles, C.E., 

 constructed an embankment upwards of 100 yards above high water spring 

 tides. The seaward slope is now submerged every tide; and as it was not 

 designed for such a situation, it has been occasionally broken through, almost 

 entirely reconstructed and considerably raised. 



Great watchfulness is exercised by those who have charge of the embank- 

 ment; for if the sea were to make good its entrance through any breach, 

 a large tract of meadow country, nearly 3000 statute acres, would be sub- 

 merged in their whole extent to the docks at Birkenhead. 



These meadows are part of the tidal area which had been reclaimed, and 

 was formerly submerged through Wallasey Pool. 



Liverpool, August 1856. Joseph Boult. 



[With respect to the tables D, E, F, and G, by which this Report is ac- 

 companied, it should, perhaps, be observed that they are to be regarded as 

 only approximations to the truth, and not as representing the absolute areas 

 of the channels, or volumes of the banks; and they are merely intended as 

 gauges for comparing the growth or decline of the various features included 

 in them. The truth of the observation would be apparent to all who had 

 inspected the surveys ; it is recorded here for those who have not had the 

 opportunity of doing so.] 



The Report was illustrated by the following charts and tables : — 



A. — Plate I. Admiralty Chart of Liverpool Bay, corrected to 1847, with 

 Contours from Surveys bv Collins, 1689 ; Eyes and Fearon, 1756 ; Thomas, 

 1813. 



B. — A Chart of the Approaches to Liverpool, by Lieut. Lord, R.N., 1852, 

 with Contours from Denham, 1837; Lord, 1840; and Lord, 1846. 



C. — A Chart of the Approaches to Liverpool, by Lieut. Lord, R.N., 1854 ; 

 with Contours from Lord, 1852. 



D, E, F. — Tables, showing the average depth below low water of ordi- 

 nary Spring Tides, and the average sectional Area of the Crosby and Rock 

 Channels, computed from the Surveys of 1837, 1840, 1846, 1852, and 1854. 



G. — A Table, showing the average Volume of the Banks above Low 

 Water of ordinary Spring Tides, computed from the Survej's of 1837, 1840, 

 1846, 1852, and 1854. 



H. — A Plan exhibiting the space abstracted by the Corporation of Liver- 

 pool from the Tidal Water of the River Mersey during five successive 

 Periods, comprised between the years 1650 and 1843, compiled from authen- 

 tic Documents and actual Survey. 



J. — Sections of Part of Great Burbo Bank, on Planes parallel to a Plane 

 passing through the Leasowe and Formby Lighthouses. 



