John Spiller — Erosion of Suffolk Coast. 23 



formed, similar deposits were made in the interbedded detrital or 

 sea-beach materials, or conglomerates. Here the percolating waters 

 removed much of the cementing mud and the more easily soluble 

 pebbles, filling in the places thus left with copper and other mineral 

 matter. This form of deposit gives rise to our conglomerate mines, 

 such as the Calumet and Hecla, Tamarack, Peninsula, and Allouez. 



These mines are not worked upon veins, but upon old sea- 

 beach shingle, the same as if any one of your beaches here, after 

 having been covered up, should be worked for any mineral matter. 

 They are not veins and they have no sign of a vein upon them; but 

 they are simply bed deposits. 



You may ask, whence came the copper now deposited in these 

 three different kinds of safety vaults — vaults that were found by pre- 

 historic man to be thoroughly fire-proof, but which are not burglar- 

 proof, when attacked by the modern earth-robber with power drill 

 and dynamite? No one can tell whence came this copper; he can 

 only infer. 



The largest amounts of copper are generally well within the 

 series of lava-flows, and associated with or underlying the thicker 

 and heavier beds. Further, it has been seen that the general course 

 of the copper was downwards, as it extends frequently like icicles, 

 from the overhanging bed into the one that is worked, while sheets 

 of it are wrapped around the angles of the broken blocks, like paper 

 around a grocer's package. These and numerous other facts show 

 that the copper was deposited from water subsequently to the 

 fracturing and faulting of the rocks ; and that it was probably 

 originally disseminated through the lava-flows, and has since been 

 concentrated in the various banks of deposit by the percolating 

 waters, which penetrate all rocks. 



Did time permit, the evidence in behalf of all the statements 

 made here could be laid before you : these evidences are picked 

 up one by one by the earth's detectives, the geologists, who, like 

 the Sherlock Holmes's, study the ashes, the mud, and every relic 

 left by that thief, Time, in the depositories of old Mother Earth. 

 As you read the story of each coin and bill, each check and draft, so 

 we read the story of each pebble and rock ; and learn to ferret out 

 the secret deposit of Dame Nature. 



V. — Keoent Coast Erosion at Southwold and Covehithe. 

 By John Spiller, F.C.S. 1 



npHE sixteenth of May last was a disastrous date for Southwold 

 JL and the neighbourhood, for, owing to the prevalence of 

 northerly winds on this and the two previous days, culminating 

 in a moderate gale, the tides rose to an abnormal height, and this, 

 combined with a rough sea, made fearful inroads upon the soft, 

 sandy cliff and the shingle on the foreshore, washing away a large 

 piece of land and creating a new cove at the northern boundary 

 of the little town. The effect would have been worse but for the 



1 Bead before Section C at the Ipswich Meeting of the British Association, 1895. 



