THE OOLITIC SYSTEM. 725 



appears conspicuously in the Cotteswold Hills in Gloucestershire, in the beautiful hills 

 near Bath, and is represented in the north of France by the well-known Caen stone of 

 Normandy. In the neighbourhood of Bath the great oolite, or Bath stone, is accompanied 

 with thick layers of fuller 's earth, a soft aluminous marl, composed of silica, alumina, and 

 24 per cent, of water. This soil is remarkable for its property of absorbing oily matter, 

 and was once largely employed in the woollen manufacture for cleansing woollen cloth 

 from its impurities, but it is now generally superseded by the use of soap. The Stones- 

 field slate, celebrated for its organic remains, is a calcareous slaty rock, which has long 

 been quarried at the village of that name, near the town of Woodstock. The inferior 

 oolite^ a coarse limestone, with ferruginous sand and sandstone, is distinguished from the 

 great oolite by its less economic value and darker hue, derived from the greater quantity 

 of oxide of iron disseminated through the mass. Dundry Hill, near Bristol, is an inter- 

 esting outlier of inferior oolite resting on a bed of lias, in the quarries of which many 

 remains of marine Crustacea have been found. 



Among the preceding members of the lower division of the oolitic rocks, the Stonesfield 

 slate, in Oxfordshire, is of singular interest, on account of its numerous and varied fossils. 

 The village is situated in a valley, the hill-sides of which have been perforated with hori- 

 zontal galleries to obtain the slate, which divides into thin plates on exposure to frost, 

 and is used for roofing. Here occur vegetable remains, consisting of drifted fragments of 

 coniferous wood, leaves and fruits of cycadese, marine plants referable to fuci, associated 

 with shells, the relics of fishes, birds, and insects, the bones of reptiles and mammalia, the 

 latter ,. the first instance of mammalian relics that occurs in the history of the globe, and 

 the only instance that has yet been discovered in rocks of older date than the tertiary 

 strata* Among the animal exuviae, Dr. Buckland found those which enabled him to 

 establish a new genus of reptiles, described under the name of megalosaurus, a lizard of 

 great size, as the name imports* allied to the living monitor, a species of lizard which has 

 been thus styled from the groundless supposition that it gives warning of the approach of 

 the crocodile by a hissing noise. The remains of this reptile have also been met with in 

 the oolite near Besancon, in France. Though no entire skeleton has been discovered, yet, 

 from the perfect state of many of the bones and teeth, their size and proportions,, the 

 naturalist can approximate closely to the form and dimensions of the animaL It was 

 asserted by Cuvier of another reptile, that before even he had seen a single vertebra or 

 a bone of its extremities, he was able to announce the character of the entire skeleton, 

 from an examination of the jaws and teeth alone, or from a single tooth ; a result, as 

 Dr. Buckland observes, of those magnificent laws of co-existence, which form the basis of 

 the science of comparative anatomy, and which give the highest interest to its discoveries. 

 According to Cuvier, the megalosaurus must have measured from forty to fifty feet in 

 length. This enormous reptile was carnivorous* In the structure of its teeth are 

 combined the knife, the saw, and the sabre. Its food probably consisted of crocodiles and 

 tortoises. The thigh and leg bones are hot solid throughout, like those of aquatic quad- 

 rupeds, but hollow at the centre for the reception of medullary substance, like the bones 

 of terrestrial animals, and from hence it is inferred that the megalosaurus was ah inhabit- 

 ant of the land; Its remains are not peculiar to the oolite, but occur in the strata of the 

 Weald. 



But the most interesting animal reliquiae of the Stonesfield slate are several mutilated 

 lower jawg with teeth, belonging to marsupial mammalia, quadrupeds that carry their 

 young in a pouch (marsupium), as the existing kangaroo. The figure is a specimen double 

 the natural size, with seven molar teeth, one canine, and three incisors. This jaw, that 

 of a very small animal, upon being submitted to Cuvier, was pronounced to be that of a 

 marsupial quadruped allied to the opossum, a decision which has been ratified by several 



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