SCIENCE-GOSSIP. 



95 



The Barton Beds which follow are 255 feet thick 

 at the western and 162 feet thick at the eastern 

 outcrop. Fossils occur at both places but more 

 plentifully at Alum Bay, where they can be easily 

 collected, although even there the richest zones are 

 now concealed by the pier. The fauna approxi- 

 mates closely to that of the beds on the mainland, 

 although from the small extent of the exposure 

 fewer species have been recorded. 



The Headon Hill Sands form the top of the 

 Eocene Formation of the Isle of Wight. They 

 consist of pale buff quartz sand, practically 

 unfossiliferous, and are 170 feet thick at Alum Bay 

 and 184 feet at Whitecliff Bay. At the latter 

 place the occurrence of casts of Tellina and 

 Panopasa has caused them to be classed with the 

 Eocene rather than with the Oligocene, whilst 

 they constitute, in fact, a passage between the two 

 conformable formations. 



The Oligocene Beds of the Isle of Wight spread 

 out over the whole of the area to the north of that 

 already described, on the south affected by the 

 great anticlinal fold, and to the north occupying 

 the area of the sinclinal trough. 



The Headon beds are about 150 feet thick on the 

 west coast and 212 feet thick at Whitecliff Bay. 

 They are freshwater and estuarine beds, with 

 strongly marked marine conditions near the middle 

 of the series, hence their separation into upper, 

 middle and lower beds. The whole series is simply 

 crowded with fossils, which may be readily col- 

 lected in the most perfect condition, some few 

 species retaining traces of their colour markings. 

 The marine Middle Headons contain the most 

 species, but the character of this horizon varies in 

 an interesting way at different places. On the 

 south-west side of Headon Hill the marine shells, 

 whilst not uncommon, are confined to a few 

 species, whilst estuarine forms are very decidedly 

 in the majority. At the north-east side of 

 the same hill considerable change is noticed ; 

 marine species become more abundant and 

 individuals more numerous, whilst at Col- 

 well Bay the marine type is altogether in 

 the ascendant. Along all this coast the Middle 

 Headons are only about 30 feet thick, whilst 

 at Whitecliff Bay they are increased to 126 

 feet, and have at their base a true marine bed 

 with corals, sometimes described as the Brocken- 

 hurst Bed, from its general agreement with a bed 

 in a similar position at that place. This multipli- 

 cation of names is, however, unnecessary, because 

 the Middle Headons, as a whole, simply and 

 clearly indicate that the stream, near the estuary 

 of which they were laid down, came from the 

 south-west. 



The Osborne Beds are chiefly a freshwater 

 series, some 100 feet in thickness. They are seen 

 overlying the Headon Beds, on the west coast, on 



Headon Hill and in Colwell Bay, on the east 

 coast, in Whitecliff Bay, and at various places at 

 the north of the island. Freshwater shells may 

 generally be found, but at King's Quay, near 

 Osborne, there is a' bed of clay, in which Mr. 

 Colenutt, of Ryde, has discovered multitudes of 

 small fish (Clupea vectensis), evidently, as Mr. 



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Clement Reid points out, suddenly killed and 

 buried before they had time to decay. The St. 

 Helen's sands and Nettlestone grits, which occur 

 at the north-east corner of the island, belong to the 

 Osborne Beds ; they are only local formations, and 

 not now considered worthy of separate names 



