434 GEOLOGY OF THE SOUTH EAST OF DORSETSHIRE. 



precisely the same character as the chines of the coast be- 

 yond Poole Head, and of the back of the Isle of Wight, al- 

 though of less importance as a feature of landscape. 



There is another feature also which marks the character of 

 these cracks, as well as the chines, — they are all vertical on 

 the side opposite the chalk. The other, which is in the sup- 

 posed line of descent from the chalk, slopes to the crack. — 

 Thus the slope at Studland is to the north ; that on the coast 

 of Poole Bay to the east : this exactly agrees with theory. 



At the approach to the termination of the cliff, known as 

 the Red Rock, the sands assume a lively yellow and red colour, 

 closely resembling those of Alum Bay, and are mottled in a 

 variety of forms, the thickness of the beds being about 25 feet. 

 Mr. Lyell has mentioned " concentric stains " upon these 

 sands, " exactly imitating the transverse and oblique sections 

 of trunks of trees." — (G. T. ii. 283). These, however, are not 

 mere ' stains] but were produced by different-coloured parti- 

 cles of sand evidently collected around a nucleus, just as they 

 might be formed round a stone, or any other small object, on 

 the present sea-beach, 1 and are a portion of the solid sub- 

 stance of the rock itself, which has been formed by the hard- 

 ening of the collected sand. The stratification is very perfect, 

 but the rock (for such it may be called) has been subjected 

 to some after-action, since the consolidation of the beds ; for 

 the strata are traversed by lines in an opposite direction, 

 which divide the rock (without separation) into superficial 

 parallelograms ; these lines ranging through the c concentric' 

 curves, and occasionally exhibiting, on a minute scale, all the 

 characteristics of a fault, — or rather, perhaps, of a shifted mi- 

 neral vein. In figs. 53, 53 a, 53 b, 53 c, without attending 

 very minutely to the picturesque or proportional effect, I have 

 represented the bedding lines and joints ; and below, one of 

 the shifts or faults, which occurs just above the opening hol- 

 lowed by the sea, together with some of the concentric curves 

 and a fault in the sand-rock, near the church at Studland. 



1 All sandstones, of whatever geological age, exhibit similar concentric 

 curves. In the new red this is particularly exemplified, and as one good 

 example is sufficient, I would mention the columns of the porticoes of that 

 very magnificent building, the Custom-house at Liverpool, which striking- 

 ly illustrate the subject. The rock from which they are built was quarried 

 near the town. So also the old red sand-stone, and the grey-wacke, occa- 

 sionally show equally striking examples. Various instances of curves which 

 were produced round a nucleus, are traceable in the stones quarried for 

 pavement or building materials in Shropshire, Hereford and Monmouth- 

 shire, and may be well seen in the pavement at Ludlow and Leominster, 

 especially in Church street in the latter town. 



