Reports and Proceedings — Geological Society of London. 233 



remarked in the text, " this group of strata runs with singular 

 persistence throughout England and Wales." 



The price of this map is 12s. 6cZ., and as it is unquestionably the 

 best geological map of England and Wales which can be con- 

 veniently carried in the pocket, it should meet with a cordial 

 welcome from all interested in the physical structure of our 

 country. 



Geological Society ot London. 



L— March 9, 1898.— W. Whitaker, B.A., F.R.S., President, in the 



Chair. 



Professor J. W. Judd exhibited, on behalf of the Coral Reef 

 Committee of the Royal Society, the lowest core (698 feet) from the 

 boring at Funafuti (Ellice Islands), and drew attention to the 

 remarkable changes exhibited by the rocks obtained at this depth. 

 The core from this boring (a mass of material more than a ton in 

 weight) had been sent to this country by Professor Edgeworth David, 

 and was now being submitted to careful study. The last 20 or 30 

 feet of the boring was carried on in a rock which was of a very 

 soft character, and highly but minutely crystalline. Microscopic 

 examination shows that the rock is almost completely converted 

 into a mass of very small rhombohedra, the organic structures being 

 nearly obliterated ; while a preliminary chemical examination seems 

 to indicate that magnesia has been introduced into the rock to a con- 

 siderable extent. The complete study, microscopical and chemical, 

 of all the stages of the change which has taken place in this rock — 

 a study which will be undertaken by Mr. C. G. Cullis — promises to 

 throw much light on processes of rock-formation of very great interest 

 to the geologist. 



The following communications were read : — 



1. "Note on Clipperton Atoll." By Rear- Admiral Sir W. J. 

 Wharton, K.C.B., E.R.S., Hydrographer to the Admiralty. (Com- 

 municated by Sir Archibald Geikie, D.Sc, F.R.S., F.G.S.) 



This atoli, 600 miles from North America, in lat. 10° 17' N., 

 long. 109° 13' W., possesses a lagoon which is now completely cut 

 off from the sea. In this is a perfectly round hole where soundings 

 of 20 fathoms or more are reported, on the authority of Mr. Arundel, 

 and even deeper ones on that of the captain of a merchant-vessel. 

 On the coral ring there rises a mass of modified trachyte, the subject 

 of the following communication, about 60 feet in height. The great 

 depth of the lagoon and the rock -mass on the ring are not compatible 

 with the origin of the reef by subsidence or outward growth ; and 

 the possible hypothesis is put forth that this reef had grown on 

 the lip of a volcanic crater, or on an island, such as Krakatao, in 

 which the interior has been enlarged and deepened by volcanic 

 explosion. 



