58 <1E0L0GY OF THE ISLE OF WIGHT. 



In Blackgang Chine, and on either side of it, the Carstone with 

 the base of the overlying Gault is repeatedly exposed, but a little 

 north of the Chine, reaching the top of the cliff, it strikes inland, 

 its base being exposed in the hill on the south siile of the high 

 road near Cliff Terrace. 



On proceeding inland along the outcrop of the Carstone, we 

 are soon struck with the fact that it is more often than not over- 

 spread with Gault clay. The appearance o£ the ground at once 

 supplies the explanation. Over large areas the clay from the 

 Gault outcrop has sUd down and spread itself as a skin over a 

 more or less even slope of Carstone, but is still easily distinguished 

 by the hummocky appearance of the ground it occupies, as well as 

 by the charaeter of the soil, in some places the clay has flowed 

 down in the form of mud-rivers, keeping usually to the lines of 

 hollow in its descent, but overspreading also many of the higher 

 parts of the Carstone feature. The course and limits of these 

 mud-rivers or gutters may be distinguished, for many years after 

 thev have ceased to move, by the large sods of turf which have 

 been torn off and heaped in a little irregular bank along their 

 edo-es, and by the lines which still serve to indicate where the 

 mass of moving clay was traversed by Jong curving cracks, convex 

 in the direction of movement. The mud-rivers extend sometimes 

 to a distance of a quarter of a mile or more beyond the base of the 

 Gault. 



The sections along the western slope of St. Catherine's Down 

 are few and poor, but at its extreme north end pebbly Carstone 

 rests on buff and white sand. On its east side the guttering 

 of the Gault, assisted by the slight easterly dip of the strata, has 

 been more than usually extensive, but the Carstone near Wyd- 

 combe forms a characteristic feature. It may be followed round 

 the soutlx side of the house, and is seen at a small waterfall 

 350 yards south-east of it. Near here three outliers of Carstone 

 cap conspicuous hills, the lower portions of which consist of 

 white sand and sand-rock. The base of the Carstone appears in 

 two sand-pits 300 yards v, est, and the same distance north of 

 Itchall, which show clayey sand and ironstone resting on white 

 sandstone. A similar section occurs at Sheepwash, where the 

 Carstone forms a fine escarpment, corresponding to the feature at 

 Marvel Wood, which we have already described. The strata 

 being nearly horizontal, the Carstone runs for a long distance 

 along the tops of steep spurs of white sand and sand-rock that jut 

 out from the hill-side. Presenting everywhere the same ferru- 

 o-inous character, it may be readily distinguished from the series 

 below. The slipping down of the Gault is especially noticeable 

 south of Godshill Park. Redhill, where there is a good section 

 of the Carstone, has been named, like Redhill in Surrey, from the 

 ferruginous colour of the soil. 



In Appuldurcombe Park and about Wroxall, a large area is 

 occupied by slipped Gault ; but the Carstone appears by the side 

 of the road north of the village, and its base is well exposed at 

 Yard Farm, where it rests on white sand 



