RELATIONS TO OTHER BRITISH DEPOSITS. 49 



by Dr Fitton 1 in 1836, by Mr Godwin Austen 2 in 1850, and by 

 Mr Sharpe 3 in 1854. 



And here again the general relations of the bed are the same 

 as those we have been describing in other districts, the iron sands 

 resting upon the Kimmeridge Clay and Coral Rag, and being over- 

 laid by the Gault, with marked unconformity at both junction 

 lines, above and below. 



The nature of the rock (a false bedded iron sand, as much like 

 the Suffolk Crag as any other British rock) shews that we are still 

 near upon the old coast line, as at Potton and Brickhill, and the 

 included pebbles are also of the same nature, namely, Quartzite, 

 Vein Quartz, Lydian stone, Flinty altered slate rock, and Jasper 

 with (according to Mr Godwin Austen) water-worn crystals of 

 Felspar; thus shewing that the waves of the Up ware and Farring- 

 don Neocomian sea beat against one and the same old coast line. 

 The Phosphate of Lime nodules or "coprolites" also occur at 

 Farringdon, but only scantily, and are indistinguishable in appear- 

 ance from those at Potton and Upware; but here, as at Brickhill, 

 the pebbles and 'coprolites' are loosely scattered through the sands 

 and not collected into a distinct nodule or pebble bed as they are 

 at Upware and Potton, and Rushmoor Bottom, in Bedfordshire. 



Again, the close relationship of all these deposits to one another 

 is scarcely less well shewn in their included vertebrate remains and 

 'derived' fossils, than by their native invertebrate species. Here at 

 Farringdon we meet with the same vertebrate fossils, namely : 



Iguanodon. Otodus. 



Megalosaurus. Gyrodus. 

 Crocodilians (Goniopholis ? Teleo- Sphcerodus. 



saurus, and Dakosaurus). Pycnodus. 



Pliosaurus. StropJiodus. 



Plesiosaurus. Hybodus. 



Ichthyosaurus. Asteracanthus and Ischyodus. 



And the same derived invertebrate species, namely : 

 Ammonites biplex, Sby. Natica. 



mutabilis, Sby. Chemnitzia Heddingtonensis, Sly. 



excavatus, Sby. Modiola. 



sp. Area, 



fielemnites, large sp. Cardium striatulum, Sby. 



1 Strata Mow the Chalk. 



* Quarterly Journal Geol. Roc. 1850, p. 454. 



3 Ibid. Vol. x. p. 176. 



K. 4 



