90 SIXTH UEPORT. — 1836. 



stratum ; 4th, the lower marl or coarse diluvium with very few bones 

 5th, the beds of sand, extending down to the limestone rock. Again, 

 near the entrance are, 1st, the bed of sand and stalagmite forming the 

 present floor, on about the same level with the bottom of the 4th or 

 lower marl just named ; 2nd, yellow ochrey loam, with bones, &c., ex- 

 tending along the vestibule from A to 13, and passing down to the solid 

 rock, but at the entrance resting upon coarse gravel. There is no trace 

 of the oclirey loam deposit at the upper end of the cave. 



The author forbears to speculate further on the above appearances, 

 than to consider the upper series of fine silts to have been derived from 

 two different sources, viz., the red and more compact layers from in- 

 filtrations of the decomposed limestone of the cave, and the ochrey mi- 

 caceous and more friable ones from water entering the mouth charged 

 with a muddy sediment of the decomposed primitive rocks of the neigh- 

 bourhood, and having a common origin with the ■water- worn pebbles so 

 abundant within and about the cave. That the valley was occupied by 

 water to at least the level of the cave before the deposition of the ossi- 

 ferous strata, is proved by the beds of sand and smooth pebbles under- 

 neath. Immense masses of these pebbles, more or less water- worn and 

 mixed with diluvium, mask the face of the limestone rock in many places, 

 and lie even on its summit, 40 or 50 yards above the level of the cave. 

 Appeai-ances about a very picturesquely perforated rock much below it, 

 show that this diluvium must have been transported hither long subse- 

 quent to the disruption and elevation of the limestone, and that not 

 simultaneously, for the pebbles still adhere to its irregularly excavated 

 sides, and there is an intermediate horizontal layer of them of smaller 

 size. 



The author does not decide whether there are two distinct deposits 

 of bones, viz., one in the yellow loam under the vestibule, and another 

 at the upper extremity of the cave ; though the diiferent materials in 

 which they are respectively found, the disparity of level, and the inter- 

 mediate beds of sand, favour such a conclusion. 



From the concave trough-like shape of the sides about the entrance, 

 as well as from the beds of sand and gravel within, the author infers that 

 the cave must once have been a water-course ; for the abraded portions 

 have been scooped out, alternately right and left, precisely in those places 

 to which, from the opposite projections, the water-borne pebbles would 

 have been driven with the greatest force. 



On an additional Species of the newly-discovered Saurian Animals in the 

 Magnesian Conglomerate of Durdham Down, near Bristol. By Henry 

 Riley, M.D., and Samuel Stutchbuky, A.L.S.* 



The remains about to be described were found in quarrj'Ingthebrec- 

 ciated beds of dolomitic conglomerate, which rests upon the highl)'' in- 



* In March, 1836, a paper from the same authors was read before the Geological 

 Society of London, entitled, " A description of various Fossil remains of three di- 

 stinct Saurian animals discovered in the autimin of 1831, in the Magncsiau Coiiglomc- 



