Page:Transactions of the Geological Society, 1st series, vol. 1.djvu/276

 to the oxidation of the iron, though the rock itself does not act in any sensible manner on the magnet. This limestone has a superficial resemblance to iron-stone and to some basaltic rocks; passages however might be traced to the slate-clay just mentioned, with which perhaps it alternates. I found its spec. grav. 2,641. It was not in situ, but comes very probably only from a little distance.

On taking a general view of the district here described, we shall find that of the two islands which it comprehends, one, the Isle of Wight, has its greatest dimension from east to west, while the other, the Isle of Portland, extends longitudinally from north to south, or nearly so: that in the Isle of Wight, the shelving of the land, independently of the particular slopes of the hills, is from south to north, as is clearly shewn by the rise of the Medina river, and by the elevation of Niton, one of the most southern villages, situated on the back of St. Carherine's-hill. In the Isle of Portland, on the contrary, we have an uninterrupted plain, with a gradual and uniform slope from north to south, of nearly four hundred feet in a distance of five miles. No river, that I am aware of, waters the Isle of Portland, but the inhabitants are plentifully supplied with fresh water, by two very line and abundant springs.

In the Isle of Wight, the tract of land to the north of the ridge