14 J. Clifton Ward — Denudation of the Lake-district. 



Fig 



to tliese involute agates, may I tMnk be traced without a break. 

 The base of this stone is formed of smaller and less perfect crystals, 

 •which, cut transversely, present themselves in honeycomb-like 

 groups, Fig. 5. Each of these cells is a little mural agate, with no 



spherical force disturbing it. When 

 quartz disposed to such formation gets 

 mixed with jasper, or with any other 

 uncrystallizable rock, the cells become 

 shapeless, and we get results such as 

 those represented in Plate II. This 

 stone there drawn shows the combina- 

 tion of angular cells with confusedly 

 coiled ones, of which a close-set group 

 is seen on the right, gathered together 

 within broadly curved lines, which I 

 think we shall be able to trace through 

 succeeding examples, as they reduce 

 themselves to the shell-like contours of true involute agate. On 

 the other hand, in the centre of the stone, the less disciplined 

 series of jasper veins, surrounding crystalline spaces, show the first 

 origin of the groups of agate, which ultimately resemble a pebble 

 breccia. I will endeavour in following papers to trace the two 

 series through their gradual development. 



IV. — On the Denudation of the Lake-district. 



By J. Clifton "Ward, F.G.S., Associate of the Eoyal School of Mines, of the 

 Geological Sui-vey of England and Wales. 



AN interesting Article by my colleague, Mr. C E. De Eance, in 

 the last number of this Magazine, upon "The Surface- Geology 

 of the Lake-District," induces me to offer a few remarks in con- 

 nection with the subject. 



Being engaged in the Survey of part of this district, I am at 

 present professionally tongue-tied as to details, but there are several 

 general points connected with its ancient and present physical 

 geography which have not seldom occurred to me during the short 

 time I have been in the country. 



1. The enormous amount of denudation that has taken place over 

 the area in question, almost as much material having been taken 

 away in the formation of the valleys as has been left to form the 

 mountains. 



2. The utter incompetency of marine action to form the present 

 contour of the country, its complicated systems of valleys, its 

 numerous lake-hollows. 



3. The very great power of the atmosphere as a present working 

 agent ; the frequent storms, the deluges of rain, the almost constant 

 wetting of the hill-tops, the sudden changes in temperature, the 

 giant power of frost, the rushing of the wind up or down valleys 

 and round corners. 



