64 DESCRIPTION OF THE STRATA. 



presents many abrupt rocks fronting the same valley ; as these rocks, 

 forming- the northern border of the Langton Wolds, seem to mark the 

 extent of the disruption in this direction, being apparently the con- 

 tinuation of those strata which once covered the space that is novsr a 

 valley, by the breaking off and subsidence of which strata the valley 

 has been formed. On the same principle, we may account for several 

 other irregularities in these hills, particularly on the south side of the 

 valley ; where the strata are in some places very flat, and in others 

 elevated, with great variations in their dip, and not a few breaks and 

 interruptions. , 



On the north side of -the valley, the hills in general have a re- 

 markably uniform appearance. Their southern faces gently slope into 

 the valley ; their upper surface spreads into extensive flats, nearly 

 level, as in what are called table mountains; and, on the n<3rth, they 

 terminate abruptly in a steep but smooth declivity, forming an angle 

 6i about forty-five degrees with the horizon. In this respect there is 

 a striking difference between the escarpment of these hills, and that 

 ■of the chalk hills. The chalk hills, except in the sea cliffs, have their 

 north fronts rounded off", and often exhibit a chain of round knolls, 

 particularly near Heslerton; but the flat summits of the limestone 

 hills usually preserve their level to the very verge of their northern 

 fronts, and as these fronts descend in a regularly inclined plane, the 

 pi'ofile of each hill appears like the junction of two straight lines, the 

 level line and the line of escarpment. Hence, as the same angle of 

 inclination prevails almost universally, a range of projecting points 

 in the fronts of these hills, viewed in profile, presents the appearance 

 of regular works of art. 



The same uniformity is not observed among the hills on the south 

 and south-west of the valley; for though they have for the most part 

 flat summits, there is a considerable variety in the form of their fi'onts ; 

 some of them, as has been noticed, presenting bold perpendicular 



