Page:Quarterly Journal of the Geological Society of London, vol. 27.djvu/349

 in the Cowleaze series the argillaceous element preponderates, the Barnes beds are in great part composed of sand or sandstone, with subordinate bands of clay. The following is the succession of beds in Brixton Bay.

(a) Very hard greenish-white sandstone, with many nodules and reins of pyrites ; shells numerous in its upper part 1 to 2 feet.

(b) Less hard coarse greenish sandstone forming a ledge above the beds below 4 to 6 feet.

(c) Yellow false-bedded sand slightly ferruginous in its upper part, carbonaceous in places 25 to 30 feet.

(d) The lower portion of the last graduates downwards into interlaminated sands and grey micaceous sandy clays, 15 feet.

(e) Yellow and white sands 3 feet

These beds rest on the ordinary variegated strata of the Wealden, which are exposed to a thickness of from 300 to 400 feet ; but their base is not visible in the Isle of Wight.

The sandy beds of the Barnes series usually contain but few shells. The top band of sandstone exhibits Cyrena and Unio in abundance, but, owing to the hardness of the matrix and the decomposed condition of the shells, the fossils are very difficult of extraction. In places the beds contain much carbonaceous matter, with seams of lignite and masses of wood converted into jet or pyrites. One band has yielded marine shells, including oysters, Cardium, casts of Trigonia, and several univalves. The beds of the Barnes series have furnished to local collectors a rich harvest of reptilian bones *.

It seems not improbable that the thin beds (A) at the top of the section in Punfield Cove represent, in a very attenuated condition, the Cowleaze series of the Isle of Wight, while the beds below (B and C), are an expanded form of the Barnes series.

2. Compton Bay. The Punfield strata are here highly inclined, and are broken up by several faults, They are well illustrated in the section of Professor Forbes and Mr. Bristow†. The Cowleaze series, with its Cyrena- and Paludma -limestones and "beef" and " cinder " beds, is well exposed. Besides the two species of oyster, the marine bands yield Panopoea plicata, Sow. (small), Serpuloe, and numerous fish-scales. The beds, being repeated on the shore by a fault, afford great facilities for the collection of their fossils. The Barnes series presents its usual sandy characters, and is about 50 feet thick. It contains several beds with plants and insects ; but I did not here observe any marine bands in it.

3. Sandown Bay. On the south-west side of this bay the Punfield beds are quite concealed, forming low ground covered by vegetation ; but on the north-east side of the bay, below the Red Cliff, the strata in question are well exposed. By a recent slip in the cliff the junction of the Upper Neocomian and Wealden is well exposed (1870), and yields the following section.


 * Quart. Journ. Geol. Soc. vol. xxvi. p. 3.

† Memoirs of the Geological Survey, Geologv of the Isle of Wight, plate 2. fig.l.