J. Starkie Gardner — Teredo in the Eocene. 161 



Had recourse been made to boring, or even to a shaft, only, failure 

 would almost certainly have ensued, where now the most successful 

 result has followed from driving galleries. At the Lewes Road 

 Works a different state of things occurs : the springs are very much 

 smaller and nearer together, in the 2400 feet of tunnel. 



It has occurred to me that the concentration of the underground 

 water at Goldstone Bottom may perhaps tend to explain the occur- 

 rence of the basin there, the water having a freer course there than 

 elsewhere, and therefore escaping more readily to the sea, and 

 carrying away more chalk in solution. 



At the time of my visit the tunnels were brilliantly lit up, by 

 means of candles fastened to the sides, so that we could see the 

 length of the tunnels (in one case about 800 feet) and all the springs 

 issuing from the bottom. The large springs were seen to be in 

 connection with joint- planes, which, though for the most part closed, 

 or nearly so, yet, I was assured (by Mr. Baker, who accompanied 

 me), were open where the water came out, so that a man's arm 

 could be thrust in the opening. 



Some small inflows of water from the upper part of a tunnel 

 seemed to communicate nearly directly with the ground above, as, 

 though running, or rather gently trickling, at the time (after some 

 wet weather), they had not been seen before, in the dry weather. 

 It was strange indeed to see the great extent of side that was quite 

 dry, damp being the exception, and to think that, were pumping 

 stopped, the whole would be filled with water in 6 or 8 hours. 



In the North-eastern tunnel the roof is throughout of one bed, 

 rarely needing support. At the bottom of this bed of chalk there 

 was a thin, but continuous, layer of flint, which, being brittle, had 

 been cleared away. It is curious that the end of this tunnel has 

 struck on an old well, probably one that was made in the early part 

 of the century, when a number of French prisoners of war were 

 encamped on the site of the works. 



Some weak places in the tunnels had been strengthened by brick- 

 work ; but for the most part the chalk is firm enough to stand. 



To conclude, the visit to these important works, so liberally 

 opened for us by the Corporation of Brighton, could not fail to be of 

 the greatest interest to those present, and to be a source of instruction 

 to all interested in the important question of water-supply from the 

 Chalk. 



V. — Inquiry concerning the Distribution of Teredo-bored 



Wood in the Eocene. 



By J. Starkie Gardner, P.G.S. 



THE habits and distribution of this marine molluscan pest chiefly 

 concern the engineer and ship-builder at the present day, but in 

 the past their presence is a considerable guide to the geologist as to the 

 conditions under which many of the Eocene beds were deposited. It 

 does not seem to have existed in the Gault sea, for though the drift- 

 wood of this period is riddled by some of its destructive ancestors, such 

 as Teredina, Lamarck, and perhaps Xylopliaga, it is far less completely 



DECADE III. VOL. III. — NO. IV. 11 



