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From the surface downwards, the following formations were 

 passed through : — 



(a) Blown Sand. 



(/^) Alternating layers of Sand and Gravel. 



(c) A main bed of Gravel. 



(d) Boulder Clay. 



(a) The Blown Sand — which, it may be mentioned, is the 

 surface formation for many miles along the coast, and which forms 

 ranges of dunes running from east to west — averaged about eight 

 feet in depth. But it ought to be observed that, when the old 

 dock was made, and when the lines of railway leading to it, 

 and which until lately ran over the site of the new dock, were laid 

 down, several dunes, twenty to thirty feet in height, had to be 

 removed. 



{l>) The alternating layers of Sand and Gravel averaged 

 respectively about twenty inches in thickness, and together 

 occupied a depth of from eight to ten feet. In this formation 

 a shell-beach was met with, which extended across the dock, with 

 an average thickness of two feet. The shells were, for the most 

 part, entire ; and they belonged to species at present existing in 

 British waters. Oyster, Mussle, Cockle, Whelk, Limpet, and 

 Scallop shells were found in great abundance. The beach was 

 first met with about eleven feet from the surface. 



(c) The bed of Gravel was about ten feet thick throughout the 

 area of the dock. It was of enormous value to the contractors, 

 for, with the addition of a seventh part of cement, and of a 

 sufficiency of water, it made the concrete with which the dock 

 walls were built. 



(d) Immediately under the gravel came the Clay, in which the 

 foundations are all laid. It greatest thickness, so far as is known, 

 is thirty feet ; five to fifteen feet of which had to be passed through 

 to form the floor of the dock. The clay, which is red and sandy, 

 contained a considerable variety of far-travelled boulders, including 

 many of Criffel Granite. These were met with chiefly at the north 

 end of the dock ; and, at the entrance, they formed a troublesome 



