90 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. 



them was a seam of lignite (5 inches thick), which along the line of 

 the excavation (450 feet in extent) exhibited numerous small faults 

 at which the clay was always curiously contorted. Under the 

 seam of coal was a more indurated portion of the calcareous sand, 

 approaching to the character of hardened marl, and in this nu- 

 merous examples of a Univalve were found, strongly resembling a 

 Buccinum from Touraine. 



2. Account of the Strata observed in the Excavation of the 

 Bletchingley Tunnel. By Frederick Walter Simms, 

 F.G.S. M. Ins. C.E. 



A few months ago I had the pleasure of presenting to the Geo- 

 logical Society some fossils collected by me in the course of the 

 construction of the Bletchingley Tunnel, upon the line of the South 

 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 vertebras of the Iguanodon, which I presented to the 

 Museum of the College of Surgeons. Many remains had been 

 thrown away, 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 



