82 SURVEY UNDER OFFICE OF WORKS CHAP, in 



breakfasted with us.' With reference to the ' wrinkles ' 

 which the Director-General was able to furnish to his 

 younger colleagues, the following extract from a letter 

 written four days afterwards to W. T. Aveline is not 

 without geological interest : * There are a number of 

 bands of strata here, which I at first took for altered 

 rocks, but which Sir Henry declared to be volcanic 

 ash, and which, though doubtless often deposited in 

 water, he declares must be mapped in green. 1 His 

 reason is that they are volcanic products ; and I 

 see he is right. Some of them in structure are as 

 fine as porcelain - slates, being mostly or entirely 

 composed of felspar.' 



1 2<$th. Car to Drws y nant. Over Aran Benllyn 

 and Aran Mowddwy to Dinas Mowddwy. Came 

 home in a car to Dolgelli, well tired ; Sir H. the 

 freshest of us. Dined, slept, awoke, and went to bed. 



Afth September. Started. Walked down to the 

 castle [Harlech] after breakfast. Splendid ruin. From 

 thence along the coast, where we bathed. Thence to 

 Llanbedr, and across the sandstone hills through Bwlch 

 Ardudwy to Pont dol gefeiliau, where we met a car 

 and drove home by eight. Among the hills Sir H. and 

 I had lunch in a hut, where we met a Welshwoman, 

 who gave us bread, butter, and milk, and a hearty 

 welcome. 



22nd. Went with Selwyn, Oldham [see p. 84], and 

 Salter to Barmouth, etc. ; walked back across the sand- 

 stone hills over Llawllech. Jolly day. O. dined with us. 



$th October. Came up from Bala in a car with 

 Jukes 2 [who arrived at Bala on the 3rd to join the 



1 Green was the colour adopted at that time on the published maps of the 

 Geological Survey to express ' greenstones ' and other igneous masses. 



2 Joseph Beete Jukes, born 1811, died 1869; after carrying on geological 

 explorations in Newfoundland and Torres Straits, returned to England and 



