358 [Feb. 21, 



Eastern Railway. These fossils consisted of bones of the Igua- 

 nodon, Lepidotus Mantelli, and five specimens of the plant Cla- 

 thraria Lyellii. I now request the Society's acceptance of a fine 

 specimen of the Lepidotus Mantelli, which was found in the exca- 

 vation about two hundred yards from the western extremity of the 

 tunnel. 



The range of hills formed by the escarpment of the lower green 

 sand extends between Red Hill and Tilburstow Hill, and its direction 

 is nearly from west to east. Between Bletchingley and Tilburstow 

 Hill, this range sends off a spur in a southerly direction. It was 

 through this spur, in a line nearly parallel to the sand range, and 

 about a mile to the south of it, that the railway tunnel, and the 

 excavation at each end, were carried. The spur, in the line of 

 the cuttings, consisted chiefly of Weald clay. 



It was proved by the railway cuttings that this spur formed 

 part of an anticlinal axis, which, as far as I can judge, extends 

 across the Weald from the chalk of the North Downs in Surrey, 

 between Merstham and Godstone, to the chalk of the South Downs 

 in Sussex, near Ditchling. The surface waters that fall on the 

 western side of this axis form feeders to the rivers Mole and 

 Adur ; those that fall on the eastern side feed the sources of the 

 Medway and the Ouse. 



In the excavation, at the east end of the tunnel, the beds were 

 parallel to each other, and also to the surface of the ground, rising 

 westward at an angle of about two degrees. The only organic 

 remains, worthy of note, found in this part of the work, were a 

 number of vertebrae of the Iguanodon, which I presented to the 

 Museum of the College of Surgeons. . Many remains had been 

 thrown aAvay, although I had given orders to the contrary. 



As the work advanced towards the anticlinal axis, the strata 

 showed symptoms of considerable disturbance, having numerous 

 faults and displacements, which^occasioned much trouble and dif- 

 ficulty in the construction of the tunnel. On the west of the axis, 

 near the level of the roof of the tunnel, a detached mass of sand- 

 rock, about fifty feet in length, lay across our path. From this a 

 great body of water was discharged into the workings. The rock 

 disappeared abruptly. The chief fossil remains which were found 

 in the course of the tunnel works, were those before named, which 

 are now in the possession of the Society. 



The excavation at the western end of the tunnel, from whence 

 the specimen of Lepidotus Mantelli was obtained, was full of 

 faults and displacements, the strata dipping in various directions 

 from W. by N. to E., and at almost every angle from 5° to 60°. 

 This state of things caused much trouble on the south side of the 

 excavation, by the continual slipping in of the earth ; but on the 

 north side no slip took place, and the slope stands apparently well. 

 At the western end of the excavation, the ordinary dip was about 

 13° N. , 



In this cutting there were beds of sandstone, bearing a very 

 strong ripple mark ; these beds partook of the general disturbance. 



