Page:Transactions of the Geological Society, 1st series, vol. 1.djvu/264

 at this latter plane the chalk is first to be found in situ, at the distance of fifty-seven miles from the metropolis. We lose the chalk in the neighbourhood of Otterborne, five or six miles to the S.S.W. from Winchester, where we enter again into a loam mixed with flint gravel. In the Isle of Wight, the same flint gravel in loam occurs near Marsh Green in Brixton Bay, not far from the chalk hills called Brixton and Mottiston Downs.

The heath, which extends from Christchurch town to Poole, a distance of eight miles, has for its bottom the same flint gravel either in sand or in loam. It forms also the upper part of the cliffs in Christchurch Bay by Milford, Hordel, &c.

The flint pebbles found in this formation are rounded and much smaller than those which are imbedded in the chalk; they have no coat, but on the contrary, a sort of semi-transparency approaching that of amber. They have in all probability been worn by the sea.

II. Quartzose loose Sand.

It is always strongly impregnated with oxyd of iron; it presents sometimes all the varieties of colour imaginable, white, ochre-yellow, brownish-red, pink, green and black, but in all these instances the iron seems to be in a state of peroxide, as none of the rocks which the sand forms, act at all on the magnet, though the considerable quantity of this metal which they contain is readily shewn by the application of chemical solvents.

This sandy formation is to be met with in the Isle of Wight on the southern boundary of the chalk from Shorwell to Chale, but especially in Alum Bay, where it makes high, precipitous and very