564 Correspondence. 



Errors of omission are pardonable enough, but such a bit of logic as 

 this he must allow me to cry out against. 



I add a sketch section, which will perhaps make my meaning 

 clearer. 



Section across the Valley of the Ouse, at Buckingham. 

 W.S.W. c b a E.N.E. 



1 Drift Gravel. a Quarry on Stony Stratford Bead. 



2 Cornbvash. & Quarry bebiud Workhouse. 



3 Great Oolite. ' c Cemetery. 



Dotted line — supposed outline of surface before the deposition of the Drift Gravel. 



Yours obediently, 



A. H. Green. 



Monk Beetton, Barnslet, 

 Nov.lWi, 1867. 



AGE OF THE THAMES VALLEY DEPOSITS. 



To the Editor of the Geological Magazine. 



Sir, — Mr. Searles Wood, jun., in his essay on the structure of the 

 Post-glacial deposits of the south-east of England, published in the 

 last Quarterly Journal of the Geological Society, Vol. xxiii. p. 394, 

 has made some remarks relative to a paper of mine, on the Lower 

 Brick- earths of the Thames Valley, which ought not to pass without 

 notice. Into the merits of his arc- theory, in explanation of the in- 

 equalities of the present surface of the ground, I do not intend to 

 enter, nor into the question of the supposed existence of the faults 

 in certain gravels and brick-earths. What immediately concerns me, 

 is the assertion that the Thames gravel, x 4: oi section twelve, of his 

 essay, p. 409, overlies the mammaliferous brick-earths of Stonehams 

 pit near Cray ford, and his inference therefrom that there is no 

 parallel between the brick-earths of Grays and those of the great 

 pit near Crayford, which was stated to exist in my essay. In 

 coming to my conclusion, so far from neglecting the evidence of 

 super-position, I have gone over the gTound repeatedly with Dr. 

 Spurrell and Mr. Flaxman Spurrell, who have obtained a mag- 

 nificent collection of mammals from it, and know it better than 

 perhaps anyone else, and I have failed to detect the slightest proof 

 of the Thames gravel in question actually overlying the brick-earth. 

 Professor Morris also is fully pursuaded of the exact parallelism in 

 in point of time between the brick-earth at Crayford and that at 

 Gray's Thurrock. I see therefore no reason for modifying my 

 belief on that point. Mr. Wood assumes that the deposit on the 

 south of Dartford Heath, and at Hill House, is of the same age as 

 the fossiliferous- beds at Crayford ; but he adduces no proof of it 

 whatever. Whether they be or not is perhaps an open question, but 

 the fact that the brick-earths in the railway-cutting, immediately to 

 the north of Mile £ud Terrace, and not more than half a mile from 



