HARDWICKE'S SCIENCE-GOSSIP. 



123 



blocks of grit scattered profusely about and around us 

 in wild confusion. 



Examining the stone, after fracture with the 

 hammer, we find it is a bluish-grey grit, largely 

 composed of felspathic materials and almost crystal- 

 line. Indeed, at first sight, one would take some of 

 the Cambrian beds to be felstone, but a careful 

 examination will show the rounded grains of which 

 it is composed, and assure us of its clastic character. 

 Some of the blocks which have been detached from 

 the precipices above are well worthy of study, as the 

 grit contains in some cases veins of slate, usually of a 

 greenish colour, which by weathering exhibit the 

 cleavage distinctly, though the grit is unaffected by it. 

 In one block I counted no less than six bands of slate, 

 all cleaved in the same direction, the intermediate 

 grit showing no signs of cleavage. In another case 

 the weathering brought out current bedding in the 

 grit itself, though a more unlikely material to display 

 this structure it would be difficult to conceive. 



There is no doubt that geology tends to the 

 enjoyment of scenery, for many years] ago, before I 

 had practically worked at the science, I visited this 

 spot and made a sketch of the pass, approaching it 

 from Llanbedr ; but it did not yield me the same 

 pleasure then as on my last visit, even discounting the 

 fact that on the first occasion a horridly cold wind 

 was blowing through the pass, and on the last the 

 day was sunny and bright. 



After lingering to enjoy this wild scenery we had 

 to turn our faces homewards, but not before being 

 passed by three travellers, one a lady with approved 

 Alpine-stock, who walked briskly and in good style 

 through the pass. I could not help admiring the 

 swing at which they were going, and watched them 

 as far as the eye could follow, curiously wondering in 

 what way the scenery affected them. Their feelings, 

 however, were a sealed book, for they looked not to 

 the right hand nor to the left, nor heavenwards, 

 towards the summits of the mountains. They were 

 evidently "doing their distance," and could not be 

 troubled with such frivolities as scenery ! Still, no 

 doubt, they expatiated on the grandeur of the scenery 

 when they arrived at their destination, — and had 

 time. 



The sun was now getting lower in the heavens, 

 and the Rhinogs with the range extending to 

 Diphwys was dyeing deep purple, showing sharply in 

 outline against the western sky. The structure was 

 well displayed ; long low curves ending in scarps 

 taking a direction a little eastward of north, showing 

 that the strata is not bent merely into parallel folds, 

 but has a curvature in a minor degree along its major 

 axis. Arriving at the Dolgelly road, we sat down to 

 survey and sketch Cader Idris. Lighted up by the 

 afternoon sun, the long escarpment showed every 

 detail of its furrowed side, exhibiting a marked 

 contrast to the forms of the Cambrian mountains we 

 had been studying. The golden face and purple 



shadows of Cader were appropriately set off by a 

 foreground of bright green turf, with a little farm- 

 house and group of trees to the right distinctly 

 outlined against the mountain background. Arrived 

 at the Trawsfynydd station, while waiting for the 

 train we had ample time to watch the soft rosy light 

 of evening overspread the scene, while the mountains 

 beyond the Rhinogs shone in light golden tint, 

 intensified by the dark deep purple of the Cambrian 

 range to the right. This was truly, though gained by 

 considerable walking, a red-letter day. 



FEATURES IN THE NEIGHBOURHOOD OF 

 FFESTINIOG. 



Next to Moelwyn, the most prominent objects near 

 Ffestiniog are [the two Manods. One is struck by 

 the contrast of form they exhibit as compared with 

 Moelwyn and other Snowdonian mountains. A 

 geological examination shows that they are in greater 

 part carved out of massive felspathic porphyry, 

 estimated by Ramsay at 1500 feet thick. This rock, 

 as may be seen on a smaller scale, weathers into 

 rounded forms, the Manods being, in fact, bossy hills 

 formed by denudation from a bed of igneous rock, 

 ejected during the deposition of the Llandeilo beds, 

 upon the lower beds of which they repose. These 

 beds are altered by contact, whereas the slaty beds 

 above are unaltered. (See section, p. 54. Memoir of 

 Geo. of North Wales.) 



An instructive example of the rounded form into 

 which this rock weathers may be seen in a hill near 

 the slate quarry above Llyn Morwynion, from which 

 lake the water supply of Ffestiniog is obtained. A 

 climb up to Llyn-y-Manod, a small tarn lying in the 

 hollow between the two Manods, will repay the 

 exertion. Good views over Cardigan Bay and 

 towards Harlech Castle are obtained. The mountain 

 is seen to be covered with angular blocks of stone, 

 derived from its own mass. The rock weathers with 

 a rough white crust forming with the lichens thereon 

 a beautiful gray tint in the distance, with the faintest 

 dash of purple therein. Underneath the crust is a 

 reddish-brown iron stain, which no doubt is washed 

 out of the outer skin of the stone. The talus of 

 broken blocks are not bad climbing, being filled in 

 between with soil and turf, but unfortunately we had 

 not time to get to the summit. When we started on 

 this journey, clouds and mists covered the vale, which, 

 gradually lifting, showed the bright green vegetation 

 bathed in the sunlight below. 



(To be co 11 fin ued.) 



The American Monthly Microscopical 

 Journal for April contains the first part of a pro- 

 visional key to the classification of freshwater alga 3 , 

 by the editor, Mr. Romyn Hitchcock, F.R.M.S. 



G 2 



