STRATA OF TILGATE FOREST. 39 



minate depth. In this bed water occurs at the depth of thirty or forty 

 feet. 



2. Compact hmestone, of a bluish grey colour, separated by seams of 

 indurated blue marl, into layers, from three to twelve inches in thickness. 

 It forms a bed about nine feet thick, and contains the bones of two species 

 of turtle, of one or more species of crocodile, or monitor ; and the remains 

 of vegetables aUied to the euphorbite. The upper strata are a compact 

 conglomerate ; the lower are perfectly homogeneous, and Avhere in contact 

 with the clay, contain shells of the genus vivipara. 



3. YeDowish sand, and soft calcareous sandstone, alternating with thin 

 layers of compact limestone slate ; containing bones of crocodiles, of some 

 unknown animals, and of birds ; bones and plates of two species of tor- 

 toises ; carbonized wood ; remains of vegetables resembling the euphor- 

 biae, arborescent ferns, gigantic reeds ; and casts of univalves and bivalves, 

 &c. This bed is about seven feet tliick. 



4. Diluvial aggregate, composed of quartz pebbles, and rounded frag- 

 ments of chalk, limestone, and sandstone, loosely united by a coarse grit ; 

 it contains immense quantities of minute portions of bone rounded by at- 

 trition, teeth of fishes, and of lacertee. Thickness from three to six feet. 



5. Vegetable mould and loam, from one to three feet thick. 

 Total thickness of the beds above the clay, about twenty-five feet. 



In this enumeration of the strata, those fossils only are mentioned, 

 which appear to occur most frequently in the respective beds, since the 

 organic remains are distributed indiscriminately throughout the whole 

 series of deposits, although certain of them are more abundant in one 

 stratum, than in another. 



The limestone (No. 1.) is exceedingly compact, and offers great resist- 

 ance to the hammer ; it scintillates with steel, effervesces strongly with 

 acids, and varies considerably in purity. The upper part of the rock is a 

 conglomerate of a mottled appearance, exhibiting various shades of blue, 

 white, and gi-eyish green. It is composed of quartz pebbles and irregular 

 fragments of limestone and bones, imbedded in a calcareous gangue ; and 

 is interspersed with crystallized carbonate of Ume. The quartz pebbles 



