84 T. M. EEADE ON THE DEIFT-BEDS OF THE 



Mr. Searles Wood, jun., F.G.S.*, nor the work of Dr. James Geikie, 

 F.R.S.f, be neglected where they bear upon the subject in hand 

 and lend any help towards unravelling this most complicated and 

 difficult problem. 



EIVER-PASUm 



To describe in a manner that can be realized the distribution of 

 the Drift-deposits, it will be necessary to divide the country treated 

 of into local areas. The most natural division that suggests itself to 

 me is that of river-basins ; for, as will be seen further on, the nature 

 of the rocks occurring in these drainage-areas profoundly affects the 

 character of the Drift distributed in them. 



Deiets of the Basin oe the Hivee Meesey. 



In a communication to the Liverpool Geological Society in January 

 1873, entitled " The buried Valley of the Mersey," I showed by a 

 careful comparison of a number of borings, well-sinkings, and exca- 

 vations between Warrington and Liverpool that, buried and obscured 

 by drift, there exists a rocky valley, probably Preglacial, the bed of 

 which at Warrington Bridge is about on a level with the present bed 

 of the river at Wallasey Pool, about 2Q miles further down. This 

 gorge does not pass Runcorn in the line of the present river, but cuts 

 across the low-lying land upon which the town of Widnes is now 

 built. At this point its greatest depth is 76 feet below the present 

 bed of the river at Wallasey Pool. Prom data detailed in that paper 

 I also inferred that a gorge most probably exists in the bed of the river 

 between Liverpool and Birkenhead of a still greater depth. Since 

 the above paper was written I have had opportunities of examining 

 the excavations at the North Docks ; and here, again, a system of 

 lateral rocky gullies birried in drift was disclosed, one of which, filled 

 with shingle and gravel under a coating of Boulder-clay, was excava- 

 ted 40 feet below ordnance datum and further tested with an iron rod 

 to a depth of fifty-two feet below ordnance datum without being bot- 

 tomed J. And, further, I see from the Report in 1880 of Yice-Admiral 

 Spratt, the acting Conservator of the river, that borings undertaken 

 by Mr. George Hill, C.E., for the Upper-Mersey Navigation Com- 

 missioners, show that between Weston Point and Hale Head there 

 exists a deep depression. In Mr. Hill's words, " The most unex- 

 pected feature revealed by the borings is the existence of a deep 

 depression in the underlying rock about the centre of the river, the 

 sides of which appear in some parts to be precipitous ;" " the rock in 

 the depression is from 10 to 20 feet below the rock adjoining on 

 either side, or from 20 to 30 feet below the Old-Dock sill"§. 



This depression is hardly deep enough to have formed the main 

 channel ; it may have been one of the tributaries ; and such an 



* "The Newer Pliocene Period in England," Quart. Journ. Geol. Soc. vol. 

 sxx-vi. pp. 457-527. 

 t The Great Ice Age. 



\ See article by rue in the 'Builder ' on the Mersey Tunnel, February 4th 1882. 

 § The Old-Dock sill is 4'25 feet below ordnance datum. 



