similar difference in lithological character between two contemporaneous deposits in the lower oolite, which is thoroughly calcareous in the South of England, but in Yorkshire has only a single bed of impure limestone 30 to 60 feet in thickness in the midst of an arenaceous series 800 feet in depth. In our two counties we get this limestone type fairly shown only in the comparatively small Magnesian Limestone tract of the east of Durham, and its features developed, to a certain extent, in the upper part of the western Durham dales, especially in Teesdale and Weardale. The wide extent of hill-country between the Cheviots and the Tyne, several hundreds of square miles in area, and the fells and the slopes of the west of Durham, with the exception just indicated, show everywhere in their contours and Flora the distinctive features of the eugeogenous type. We will, therefore, in the first place, attempt a detailed sketch of the vegetation of a hill of this kind. Our notes refer to Simonside, which was selected as being a fair typical representative of the shale-sandstone type of moor which occupies so large a proportion of the northern English counties.
General Sketch of a Eugeogenous Hill and its Vegetation.—From Rothbury to the summit cairn, at the east end of the hill, the distance is about 4 miles. Walking up the dale on the south side we have to keep the high road as far as the little village of Tosson, and then are in a straight line between the peak and the Coquet. At 500 feet above sea-level, and 200 above the river, we pass the highest farm house, and very soon the corn fields cease, and we climb through a meadow along the bank of the streamlet which flows down from the hill to the Coquet, a tiny brook overshadowed by ash-trees and bushes of bird-cherry, hazel, and blackthorn, with Crepis paludosa growing amongst them, and a beautiful form of Rosa tomentosa, with pure white petals just tinged towards the edge with red. Then a half-drained rushy pasture (one of the rushes in which is Juncus diffusus) is crossed, and we enter upon the open moor. From where the heather begins, to the highest point of the hill, the ascent is 900 feet, and the distance is not less than a mile, but
