AROUND THE ESTUARY OF THE DEE. 



733 



thickness above high-tide level) was found to extend to below low 

 water. 



New Dock-sections near Bootle. — Further north than Egreraont, 

 and on the opposite side of the Mersey, a series of extensive exca- 

 vations are now in progress for the purpose of obtaining sites for 

 new docks. They have been visited by several geologists ; and Mr. 

 Morton, P.G.S. (in whose company I first saw these sections), has 

 given a very brief account of them in the Geol. Mag. and in the 

 Report of the British Association for 1876. Since then I have twice 

 examined them, with the assistance of Mr. Sutcliffe, the acting en- 

 gineer. An unwary visitor to No. 1 dock (going north) might at 

 once conclude that the three drifts are there very strikingly displayed 

 — the upper clay, middle stratified sand and gravel, and a great thick- 

 ness of lower clay. What can be plainer ? he might say. A close 

 and leisurely inspection, however, would show that his upper-clay 

 had been artificially redeposited over a considerable thickness of Post- 

 glacial sea-sand with numerous shells. The last time I examined 

 these excavations a number of new and instructive sections were 

 in course of being exposed (see fig. 3). In one spot a group of 



Pig. 3. — Section exposed in the second New-dock Excavation, 



April 1877. 



A. Postglacial sand, about 6 feet ; B. Upper Boulder-clay, about 12 feet, sepa- 

 rated by a very distinct line from C, current-bedded middle sand and line 

 gravel, a sprinkling of which is continued along the line of junction between 

 the two clays ; D. Lower Boulder-clay, with an average thickness of about 

 12 feet ; E. Triassic sand and rock in situ. 



workmen stood on the partially uncovered and well-defined top of 

 the lower clay, wielding spades, with which they speedily removed 

 the upper clay*, while a throng of navvies, armed with picks, were 

 attacking the base of the lower clay, which had been found to be 

 too compact and stony to yield to spades. Towards its base the 

 lower clay might be seen graduating both horizontally and verti- 

 cally into masses of rounded gravel (partly consisting of erratic 

 stones) or into sand ; and I was informed that in some places much 

 sand had been found beneath it. The line of junction between it 

 and the underlying Triassic sand and sandstone-rock could be easily 

 traced. In several places (during a former visit) I found the middle 



* Where fresh faces have been exposed by clay-slips, the upper clay here 

 shows more or less of the grey partings by which it is generally, but not always, 

 characterized. 



