3251. In what stratum are you there? --- I have not got any samples of the strata.
3252. You have taken no borings or anything of that sort? --- No.
3253. When you get a little higher up the tube towards the north, it narrows into a blue tube and a red tube? --- Yes.
3254. Each of those represents a different tube? --- Yes.
3255. There are four altogether? --- At the start there are four altogether.
3256. Of what are those tubes made? --- They will be the ordinary type of London tube, rather large in diameter.
3257. That ring construction? --- Yes, but we are not bound to that. We might have ferro- concrete in places where it is dry.
3258. Had you thought of driving the tube in the same way as a London tube is driven? --- Yes, precisely.
3259. Are you, there, in the London clay? --- There is a good deal of London clay about there, but whether we are in it all the time I am not prepared to say, nor could anyone say without a considerable number of borings.
3260. You would not know whether you were going to drive it with a Greathead shield or not? --- I do not think it makes any difference what you are going through, whether you use a Greathead shield or not.
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