Clay with Flints is a formation covering a good deal of our Chalk. It is partly débris of the chalk formation and partly of clay beds which once rested on the Chalk. In places it is 20 feet thick. Some of the best timber in the county grows upon it. Gravel covers a good deal of the surface in Berkshire. It is found both on the high ground and in the valleys. The high-level gravels are often over 10 feet thick and the valley gravels are more than 20 feet thick in several places. Windsor, Bray, Maidenhead, Cookham, Twyford, Wokingham, Reading, Theale, Pangbourne, and Newbury stand partly or wholly upon gravel. Alluvium, the modern deposit of the rivers, covers a good deal of ground in some places, more especially in the valley of the Kennet. Sarsens are blocks of sandstone which are found on or near the surface of the ground or in the beds of gravel. They were probably derived in part from the Reading Beds and in part from the Bagshot Beds. The illustration on page 40 shows three sarsen stones lying at the bottom of a thick bed of gravel in a gravel pit on Chobham Ridges. The locality is in Surrey, but not far from the Berkshire border, and similar examples occur in Berkshire. 7. NATURAL HISTORY. The fertile district of the Vale of White Horse, the wide chalk downs, and the forest country with its sandy tracts covered by heather or pines, together with the river Thames and its tributaries, give us a considerable variety of soil, of climate, and of general conditions; and we consequently have a large variety of species both of animals and of plants, though being an inland county, many forms which people the coast are absent, or merely come as rare visitors. Naturally, too, the increase of population and the advance of civilisation have caused a great change in animal and plant life. Many species, once common, are no longer to be found and many new species have been introduced. Probably the most imposing of the animals which have roamed over our district since the advent of man was the form of elephant known as the mammoth. It possessed enormous tusks and was covered with long coarse hair with an under pelage of short woolly hair so as to be fitted for life in a cold climate. Its bones have been found in several places in Berkshire, and teeth from Abingdon and Reading are in the Reading Museum. The rhinoceros once lived in Berkshire, for bones, probably belonging to a woolly species, have been found in a railway cutting near Chilton. Bones of the bear, wolf, and bison have been found in the Drift deposits, and the wild boar was hunted in Berkshire in historic times. The badger is a harmless animal which lives a quiet life, spending the daytime in a burrow, often in a fox earth, and only coming out at night. It is in consequence much more common than is generally supposed, and our county forms no exception.