1869.] WARD — KKAEESBOEOUGH GEITS. 291 



Mr. Eyaists agreed with the author as to the difficulties presented 

 by the Lake theory in accounting for the terraces, especially those 

 not in Glen Eoy itself, but in the valley of the Spean. He called 

 attention to the part which sheep and other animals had played in 

 the preservation of the Parallel E-oads, the vegetation on which, in 

 consequence of their being more frequented by the animals, was of 

 a different character from that on the other parts of the slope. 



Mr. H. M. Jenkins objected to the supposition of the sudden 

 alteration in the level of the water adopted by the author. He 

 thought the gradual sinking of the water was quite compatible with 

 the formation of the roads. He instanced the formation of terraces 

 in gravel-pits filled with water. 



Sir H. James announced that the Ordnance survey of the district in 

 question was now complete. 



4. On Beds of supposed Eothliegende Age, near Knaeesboeough, 

 <Sfc. By J. Clieton Waed, Esq., E.G.S., of the Geological Survey 

 of England and Wales. 



By permission of the Director- General of the Geological Survey lam 

 enabled to lay before the Society a brief outline of some observations 

 made during the past summer in the course of my professional duties. 



In the neighbourhood of Knaresborough occur certain very well- 

 marked and distinctive grits of a red or purplish-red colour ; for the 

 most part these rocks are coarse, frequently quite conglomeratic; 

 oftentimes, however, they are mere sandstones, while in some places 

 they pass into sandy shales. In some localities, as near Plumpton, 

 the proportion of red felspar in the grit is very great, while in 

 otliers white specks of decomposed mineral matter are scattered 

 profusely through the mass. The quartz-pebbles are very often as 

 large as pigeons' eggs, and form well-marked layers, generally at 

 the base of the separate beds of grit. 



The grit in the neighbourhood of Plumpton, near Knaresborough, 

 forms most picturesque weathered masses. Between Spofforth and 

 Plumpton, on the slope immediately below the magnesian-limestone 

 escarpment, stand numerous detached pillars and masses of rock, 

 some rising 15 feet above the level of the surrounding ground, 

 others but barely protruding, their surfaces presenting all those 

 curiosities of atmospheric action, in the shape of perforations, basin - 

 holes, honeycombing along the planes of bedding, &c., which, 

 although in many cases difficult to explain fully, yet seem still to be 

 in process of forming. The soil of the fields in which these detached 

 and picturesque rocks rise consists, as one would expect, of the de- 

 composed grit, and seems of a very shifting nature. 



On the age of this Plumpton grit I wish now to offer a few 

 remarks. By some geologists it has been described as Permian and 

 the equivalent of the Bothliegende of the Germans ; by others it has 

 been assigned to the millstone -grit series. 



1. Authorities for Permian Age. — Prof. Sedgwick (in his paper 

 upon the magnesian-hmestone series in vol. iii. of the * Trans- 

 actions ' of this Society) speaks of these rocks as forming the base of 



