8 GEOLOGY OF THE ISLE OF WIGHT. 



9 feet thick, on the west side of Shippard's* or Compton Grange 

 C'hine, the last-mentioned rock being of a pinkish hue from the 

 abundance of grains of pink quartz in it. At 190 yards distance 

 from this chine we see the purple strata pass up into characteristic 

 blue Wealden Shales with abundant Cyrena, Paludina, Cyprids, 

 fish-remains, and fragments of ferns. These blue shales, which, 

 like the Cowleaze beds, are iuterstratified with sands in the lower 

 part, are about 222 feet thick, and are fully exposed up to and 

 in a small chine 350 yards west of Compton Grange Chine, but 

 beyond this they have been disturbed by slipping. They seem, 

 however, to be succeeded by red marls at a point in the top of the 

 cliff 50 yards west of the small chine, whether by a fault or natural 

 superposition will be discussed subsequently. 



Continuing along the top of the cliff, where the strata are 

 in place, Ave see a thickness of 193 feet of purple marls with 

 irregular white sand-beds and with three beds of grey or white 

 clay and sand with lignite, the highest and lowest containing 

 large tree trunks in addition to a great abundance of small 

 fragments of wood. 



These variegated strata pass up into blue shales and sandstones 

 jvith bands of ironstone, which in the exposed parts have 

 weathered into a cinder-like rock. About 27 feet of these blue 

 deposits are seen in place, and they are followed by blue paper- 

 shales with Cypris and slabs of Cyrena limestone with fish-bones, 

 seen- only in slips, but estimated to have a thickness of 65 feet. 

 These are overlain by the Lower Greensand. 



The question now arises whether the blue shales last described 

 are the same beds as those near Compton Grange, the strata being 

 repeated by a strike fault with a downthrow to the south ; or 

 whether there are two horizons at which this type of the Wealden 

 eeries makes its appearance in the Isle of Wight, as on the mainland. 



It is in favour of the theory of a fault, that neither at Atherfield 

 5 miles distant^ nor at Sandown ] 5 miles distant, nor at Punfield 

 20 miles to the west, can more than one group of shales of this 

 type be seen, and that only at the top of the Wealden series. 

 The thickness also of the beds visible between Brook Point and 

 the top of the lower blue shales is much the same as that between 

 Brook Point and the top of the Wealden Shales of Shepherd's 

 Chine, namely, at the former locality 676 feet, of which 454 

 are variegated, and in the latter 754 feet, of which 562 are 

 variegated. The blue shales, moreover, strongly resemble the 

 beds of Cowleaze and Shepherd's Chines. 



But on the other hand, the differences in the two sections of 

 Compton Bay are so great, though only a quarter of a mile 

 apart, that even allowing for the variability of Wealden strata, 

 it is difficult to suppose that the same set of strata appears in 

 each. The variegated beds of the upper part are characterised 

 by an abundance of lignite associated with white clays ; in those 

 below lignite is scarce, but several bands of sand-rock stand out 



* Not to be coufoundcfl with Shepherd's Chine, nc;ir Atherfield. 



