4 The Eocene Formation of Headon and Alum Bay. 



tinted sands unfossiliferous. But amongst them occurs a bed of 

 pi)5e-clay full of vegetable remains belonging to subtropical genera. 

 They are distinguished by a predominance of leguminosae, but 

 gigantic Euphorbias {Claytia Aglaivejilia) , fig trees of enormous 

 size, mingled with the palm-like Aralia, and great quantities of 

 laurels, besides oaks and conifers seem to have been the forest 

 trees of the period. [Laurel exhibited]. 



Next above these come the Bracklesham beds consisting of 

 sands, yellow, white, and crimson, wholly unfossiliferous in 

 Alum Bay. But the same strata at WhiteclifT, though of a 

 green colour and mixed with clays, contain Cardita, Turritella, 

 and Venus. 



It is to these beds too that the lignite formations so conspi- 

 cuous on the shore belong. These alternate pretty regularly with 

 beds of clay and marl, corresponding in this respect to the regular 

 coal measures which always rest on a clay bed. 



Over these lie the Barton clays, by far the richest in 

 fossil remains. They are wholly of marine origin. The lowest 

 beds are full of crushed shells of the Turritella, Fusus, Conus, 

 and others. Above these is another bed of perfect shells with 

 Nummulites, Rostellaria, Typhis pungens, Voluta luctatrix. 

 Instead of enumerating these, I will beg you to examine the 

 specimens laid before you. I may add that the vertebrates are 

 here represented by a shark called the Lamna, of which however 

 I have no specimen to exhibit. 



The Upper Bagshot sands which succeed the Barton clays are 

 destitute of fossils, but at Whitecliff, ferruginous casts of certain 

 bivalves are found, though in a very friable state. These sands 

 are extensively used for the manufacture of glass, and are 

 shipped from Yarmouth to London and Bristol at the rate of 

 3,000 or 4,000 tons per annum. 



II. We now come to the Lower Freshwater Formation, other- 

 wise called The Lower Headon Beds. At Headon these are 67 

 feet thick and appear in a series of sandy calcareous and argilla- 

 ceous marls, sometimes with more or less of a brownish coaly 

 matter. Some of them seem to consist almost entirely of frag- 

 ments of freshwater shells of the genera Lymneus Planorbis, 

 and Helix, with a bivalve resembling the Mytilus. They may 

 be seen best at Warden Ledge. Here, when the clay underneath 

 gives way owing to rain or frost, large masses fall down and are 

 used for building purposes. Following this stratum up into 

 Colwell Bay, we find that it dips to the north, after which it is 

 soon lost. But it appears again at Weston Chine and also at 

 Whitecliff, where however the limestones are replaced by clays 

 and marls. 



