NOTES ON GEOLOGICAL RESULTS. 



285 



a whitish green prove to be the same felsite as at the Corbiere 

 it would be of interest to determine whether it, or the green- 

 stone on which it lies, is the newer. 



I have found light-coloured felsites at L'Islet and at other 

 places, but I have not yet been able to determine their 

 structure. 



Superficial Deposits. 



Of this branch of my subject I shall say very little, but 

 during the excursions to the Yale under Mr. Hocart's guid- 

 ance, I was able to add a few notes to our geological detail 

 and to show the members present a much greater extent for 

 raised beach at Noirmont. 



Under this head I would like to add that I havo found 

 old beach deposits at fifty feet (about) elevation at Hountel, 

 Mont Cuet and Gruneaux quarries. 



I have also a new level, or what may prove to be a 

 neAv level for a beach, but it is not a raised beach, for it is 

 fifty feet below the soil, and on the sea coast at Rocquaine. 

 As far as I can at present gather, it is two feet below O.D. 

 It was met with in excavating a well on the property of Mr. 

 Robilliard. 



This has to be confirmed and I suggest that the Society 

 shall make this one of its excursions next year. 



If I am permitted I shall add to these notes the results of 

 one of my own little excursions. On the table you will 

 observe a large block of stone. This was shown me by Mr. 

 Micolle, of the Grands Camps Quarry, and I have secured the 

 specimen for the museum. It forms part of a structure said 

 to have been forty feet in length, but broken up by blasting 

 before its nature Avas known. You will see that there is a hollow 

 tube in the stone which probably had originally a circular 

 section but is now an oblong of 9 inches by 6 inches. This 

 tube has been scored out and refilled by the same stone, a 

 granite. I believe that it is an outlet from a deep-seated cavity 

 forwater and steam and there are marks of scoring which show 

 that stones were ejected in quantity.* It is in fact the remains 

 of a past geyser, but the peculiarity is that after it served 

 its purpose of a vent it became filled with the liquid magma 

 of granite. The core is quite distinct and has not suffered 

 nearly as much as the tube from the effect of heat and steam. 

 The tube is altered for two or three inches around the vent- 

 bore, whereas the core has a skin of altered rock only. 



* It may be a " pipe " at a long distance from a cavity of volcanic origin. 



