In the Island of Sheppey near the mouth of the Thames, the thickness of the London Clay is estimated by Mr. Prestwich to be more than 500 feet, and it is in the uppermost 50 feet that a great number of fossil fruits were obtained, being chiefly found on the beach when the sea has washed away the clay of the rapidly wasting cliffs. Fig. 205: Nipadites ellipticus. Mr. Bowerbank, in a valuable publication on these fossil fruits and seeds, has described no less than thirteen fruits of palms of the recent type _Nipa,_ now only found in the Molucca and Philippine Islands, and in Bengal (see Fig. 205). In the delta of the Ganges, Dr. Hooker observed the large nuts of _Nipa fruticans_ floating in such numbers in the various arms of that great river, as to obstruct the paddle-wheels of steamboats. These plants are allied to the cocoanut tribe on the one side, and on the other to the _Pandanus,_ or screw-pine. There are also met with three species of _Anona,_ or custard-apple; and cucurbitaceous fruits (of the gourd and melon family), and fruits of various species of _Acacia._ Besides fir-cones or fruit of true Coniferæ there are cones of Proteaceæ in abundance, and the celebrated botanist the late Robert Brown pointed out the affinity of these to the New Holland types _Petrophila_ and _Isopogon._ Of the first there are about fifty, and of the second thirty described species now living in Australia. Ettingshausen remarked in 1851 that five of the fossil species from Sheppey, named by Bowerbank[4] were specimens of the same fruit (see Fig. 206), in different states of preservation; and Mr. Carruthers, having examined the original specimens now in the British Museum, tells me that all these cones from Sheppey may be reduced to two species, which have an undoubted affinity to the two existing Australian genera above mentioned, although their perfect identity in structure cannot be made out. Fig. 206: Eocene Proteaceous Fruit (Petrophiloides Richardsoni.