72 



C. MOOEE 0]ST ABNOEMAL GEOLOGICAL 



be first noticed will be that embraced in the southern escarpment of 

 the Carboniferous Limestone, extending from Kedland, its eastern 

 end at Durdham Down, to the suspension-bridge at Clifton, over- 

 looking the river Avon on the west. 



Near the Old Black Boy inn, just under the edge of Durdham 

 Down, there are places known as The Quarry and The Quarry 

 Steps (see fig. 1). Standing on the latter, we look down into a large 

 excavation, which must have been formerly extensively worked for 

 stone, but is now occupied by small houses and gardens, most of which 

 are probably a century old. One of these houses is close under the 

 flight of steps leading to The Quarry, and has been built against a 

 natural vertical wall of mottled red or yellow unstratified limestone, 

 differing altogether in colour and texture from the grey Carboniferous 

 Limestone of the district, by which, on either side, it is bounded. It 

 is about 8 feet in thickness, and may be traced on the east side of 

 the excavation by its brighter colouring ; and there is no doubt that 

 it continues into the limestone of Durdham Down immediately above. 

 As was the case with the workings on the Mendips, the old quarry- 

 men here extracted the purer limestone, leaving the impurer some- 

 what conglomeratic infillings standing out, and terminated their 

 quarry on the east by this large dyke. As it has not been opened 

 up, little examination could be given to it for organic remains, which, 

 from its close proximity to the Thecodont deposit, would have been 

 desirable ; but that some are present therein is sufficiently indicated 

 by the fact that, after examining a few pounds weight of the softer 

 material taken from the interstices or sides of the vein, I obtained 

 numerous minute fragments of bone or teeth, one very small fish- 

 tooth, an Echinus- spine, a few joints of Carboniferous-limestone 

 Encrinites, and some of the tubes previously referred to. 



The platform of the Quarry Steps rests upon the surface of the 

 above dyke. Looking from it, along the Down escarpment to the 

 west, the eye takes in Bellevue Terrace, on the edge of the ' Down ; 

 and it was between these houses and the quarry, a distance probably 

 of 200 yards, along the same face of limestone and on the same 

 horizon, that the deposit containing the Thecodontosaurian remains 

 was found. Unfortunately the precise spot is unknown ; and, from 

 its being built over, there is not much hope of its being again 

 identified. 



My late friend, Mr. W. Sanders, P.R.S., of Clifton, gave me, some 

 years ago, a sketch showing the conglomerate on the edge of the lime- 

 stone, with what was then considered to be ]Sfew Red Sandstone at its 

 base (fig. 2); and it is significant that he does not so much represent 

 it as a basin -shaped depression in the limestone as indicate a deposit 

 following the slope of the escarpment, similar to the case of a vein 

 the top of which was opened up, but from which the limestone still 

 resting below against its side had not been removed. Mr. Sanders 

 also marks the spot where the reptilian bones were supposed to be 

 found. 



At the time "when these reptilia were discovered, the peculiar 

 conditions of deposition I have indicated were unknown. In the 



