1 876 REVISION WORK IN NORTH WALES 337 



It is a most important point in British Silurian geology, 

 as I have long attempted to show, and if I find this 

 additional demonstration I shall be glad. 



I shall be at work in Wales, writing the Memoir, 

 with some field-work, for a good while, how long I 

 know not. In September I go to Gibraltar for the 

 Colonial Office and the authorities at Gibraltar, with an 

 assistant. All expenses for both will be paid, and I 

 asked nothing more, considering it a piece of duty. 

 It is in re water. Now I would like much if you 

 could spare your brother James to go with me. A 

 few weeks will do it, for the surveying will be brief. 



In accordance with his plan of work Ramsay this 

 summer revisited many parts of the ground in North 

 Wales which Selwyn and he had surveyed so long 

 before, and with the assistance of some of his col- 

 leagues traced in the new boundaries. It is interesting 

 to notice among his notes of these journeys that over 

 tracts where formerly he had eyes only for the old 

 rocks and their structure, he now looked out eagerly 

 everywhere for the tracks of glaciers and ice-sheets, 

 examined the rock-basins, and went carefully over the 

 exposures of drift. 



BEAUMARIS, io//fc August 1876. 



MY DEAR GEIKIE We started at eight yesterday 

 morning, and had twelve hours on the Caernarvon- 

 shire hills. We began by marching to the top of Moel 

 Tryfaen to see the Cambrians and the shell-beds of 

 Trimmer, 1 1 50 [correctly about 1400] feet above the sea. 

 These are undoubtedly true marine, beachy, false-bedded 

 sands and gravels, overlaid by good boulder-clay, and 

 have been much eroded before or during the deposition 



