Corresjjondence — A. H. Hunt. 285 



By another friendly critic a well-grounded objection has been 

 raised to the proposed term ' Cambrian Ice-sheet,' on account of the 

 risk of confusion with the common stratigraphical use of ' Cambrian.' 

 It would, perhaps, be safer to fall back upon the phrase ' Welsh Ice- 

 sheet ' (with subdivision into ' North Welsh ' and * South Welsh ' if 

 found desirable). 



As previously stated, my more immediate object is especially to 

 urge the adoption of names for the (hypothetical?) ice-sheets of our 

 sea-basins, for which I have recently felt the pressing necessity. 

 On the terms proposed for the land-areas I do not at present lay 

 much stress, though it would be convenient if these could be fixed 

 at the same time. G. W. Lamplugh. 



TONBRIDGE. 



April 6, 1901. 



THE SODIUM OF THE SEA. 



Sir, — I am extremely obliged to Mr. Fisher for his kindly notice 

 of my communication concerning the " Sodium of the Sea," but feel 

 at a loss how to reply, owing to uncertainty as to whether Mr. Fisher 

 has considered and rejected De la Beche's articles on Granite and 

 Elvan, Divisional Planes, and Mineral Veins and Faults ; or, has 

 possibly overlooked such an ancient authority. 



In addition to all that De la Beche and Dr. Sorby have written, 

 and since the last edition of the " Physics of the Earth's Crust," we 

 have the additional fact that all the types of fluid inclusions found 

 in granites may be matched in different quartz-veins, so that all the 

 arguments based on the fluid inclusions in igneous magmas must be 

 prepared to meet the cases of the veins. My object in writing was 

 not so much to defend the sea-water hypothesis, as to remind 

 geologists that it existed. Throughout ray own early training I was 

 never allowed to forget that the weakest link in a chain is the 

 measure of its strength, and I knew full well that the slightest slij) 

 in fact or argument involved public castigation in the Transactions of 

 the Devonshire Association. If any of the younger geologists in 

 Devonshire erred in discipline our captain, William Pengelly, rarely 

 failed to pipe all hands on deck to witness punishment. Mr. Fisher, 

 I expect, will agree with me that in the present day it is considered 

 of far more consequence that a theory should present a solid 

 appearance than that each link should be tested, and if defective, 

 rejected, not only by the purchaser but by the chainmaker himself. 



A. E. Hunt. 



FOXW'ORTHY, MoRETONHAMrSTEAD. 



May 7, 1901. 



INTERNATIONAL GEOLOGICAL CONGRESS. 



Sir, — I regret that I omitted to express my thanks in my paper, 

 " Geological Notes on Central France," published in the Geological 

 Magazine (February, 1901, p. 59), to the Directors, MM. Boule, 

 Fabre, and Martel, for their kindness and consideration during the 



