ON THE HIGHER EOCENE BEDS OP THE ISLE OF WIGHT. 415 



tile clays, literally choked witli leaves. A remarkable peculiarity, shared 

 by every one of these leaf beds, is that they are almost wholly destitute of 

 any traces of animal life except the disarticulated wings and wing cases of 

 insects. It is difficult to imagine how it has happened that these vast 

 and recurring accumulations of fine silt, well fitted to preserve the most 

 delicate organisms, should not at all events abound with the remains of 

 freshwater fish. They were formed in the beds of rivers of various dimen- 

 sions, some of great magnitude, and in the higher as well as the lower 

 reaches. Yet throughout the twenty odd years I have been collecting 

 in these at home and abroad, I have never so much as found a fish scale 

 nor aquatic insect in any plant bed, unless newer in age than the Bag- 

 shot. It may appear a bold inference to draw, but the only one possible is 

 that freshwater fish did not exist in our area in Eocene times. All other 

 explanations, such as difference in powers of flotation, drifting, decom- 

 position, break down on examination. Plant beds of the same character 

 but of later date, in France, Germany, &c., abound in fish and insects ; 

 and in some cases, as at Cereste, the number of feathers accompanyino- 

 them seems to indicate that this food supply had speedily led to the 

 development of aquatic bird life. The English Oligocenes are no excep- 

 tion to the rule, and in place of its former almost oppressive absence, 

 they teem with aquatic life in many forms, and scarcely a plant bed 

 thenceforward is unaccompanied with animal remains. 



This new state of things begins in our area in the Headon, and partly 

 on this account collecting fossil plants in these higher beds is far from easy. 

 The superabundance of aquatic life, especially mollusca, is antagonistic 

 to the preservation of plants. Most leaves preserve their forms in water 

 for many months, if perfectly undisturbed, and would in time become 

 covered by films of silt, to be compacted eventually into the finely 

 laminated clay which constitutes a leaf-bed. But on a bottom in- 

 fested with life they would rapidly break up when decay set in, and 

 silt largely mixed with dead shells is not a good medium to preserve 

 them. It is only here and there in the Hampshire Oligocenes that plants 

 are found in good preservation and the patches are small and local, so 

 that, unless a collector happens to be present when they are exposed, 

 their contents become lost. This circumstance always renders it doubtful 

 whether a special search for plants will be rewarded, and disappointment 

 has more often resulted than the reverse. Hence while we have oreat 

 collections from the British Eocenes, which may teach the succession of 

 vegetation that occupied our area, our Oligocene flora is only repre- 

 sented by small groups of plants in widely scattered collections, so that it 

 is not easy to form an idea of it as a whole. 



A former grant enabled the Lower Headon flora of Hordwell to be ex- 

 plored as far as possible, and the present one has enabled us to obtain a 

 satisfactory insight into the newer Oligocene floras of the Isle of Wight. 

 Some account of the former has been given in a previous report. As 

 au illustration of the local distribution of plants in our Oligocenes, I may 

 mention that a large number of specimens of palms from Hordwell were 

 sent to Belgium, a mass of them in a solid matrix having been exposed 

 during a few tides, whilst a foreign collector happened to be visiting 

 the spot. Some pieces of feather palms, obtained on another occasion 

 by Mr. Keeping, have been figured for the Palseontographical Society. 



Unlike the Lower Headon, the Middle Headon, an almost purely 

 marine deposit, seems completely barren of plants. 



