98 Correspondence — Rev. 0, Fisher, 



communications, and Dr. Hunt is quite entitled to make the most of such a 

 bhmder, if he considers it will support his views ; at the same time I trust that he 

 will also be equally candid in cases where he may be found tripping. 



Dr. Hunt alludes to a rough sketch of some of my views contained in the 

 Geological Magazine ; but as I have already accepted the invitation of the 

 Council of the Chemical Society to give a lecture on Chemical Geology (20th 

 February next), Dr. Hunt will thus be enabled to take my views into full con- 

 sideration, and after comparing them with his own 1 trust he will give us the 

 benefit of his scrutiny ; for as I regard the ultimate object of all my labours as 

 being the attainment of scientific truth, I am as fully prepared to be corrected in 

 points where I may be proved to be wrong as to defend those which I hold to be 

 right. 



THE BOULDER-CLAY AT WITHAM AND THE THAMES VALLEY. 



Sir, — Mr. Dawkins has spoken of the occurrence of a Boulder-clay 

 at Witham as affording a presumption that the valley there is older 

 than the glacial drift. I am able to give a rough section of the 

 boring for the well in v^hich it occurred, where I saw it in 1865. 

 I obtained the depths from the men at work, in answer to questions 

 regarding the stuff which I saw to have been brought up. 



SECTION OF ARTESIAN WELL AT WITHAM STATION, ESSEX. Feet. 



Coarse gravel 20 



Greyish Glacial clay, with large flints and chalk pebbles 150 



Fine clayey sand, brown and green, with green-coated flints at the bottom, 



(Thames sand) 10 



Chalk, in which the water was obtained. 



The spot is more than 20 feet above the stream, so that the gravel 

 is a terrace gravel ; and, in what is probably the same bed, I found 

 a short time previously a good specimen of an oval flint implement : 

 I picked it off a heap in the gravel-pit, at the entrance of the lane 

 which leads to the Goods' Depot. 



Now, as regards the glacial clay in this section, there is a pecu- 

 liarity which at the time surprised me much. I allude to the entire 

 absence of anything like the " middle drift" beneath it. This drift 

 occurs in full force along the high ground to the south, by Danbury 

 and Wickham Bishops ; and Mr. S. V. Wood, jun., has shown it in 

 section 9 of his paper on the Essex valleys,^ as underlying the Boulder- 

 clay at Little Braxted close by. A glance at that section will show 

 that the position of the Boulder-clay at Little Braxted has no analogy 

 with that at Witham Station, where it extends many feet below the 

 bottom of the valley. These circumstances, to my mind, throw a 

 considerable doubt upon the clay at the station being the true 

 Boulder-drift ; and if it be not, we cannot argue from it that the 

 valley is older than the Boulder-drift. 



We are told of the existence of several Boulder-clays — and I can 

 myself speak to a Boulder-clay occupying a valley in Essex which is 

 clearly newer than the true Boulder-drift. It is to be seen on the 

 shore, beneath the terrace, at Walton-on-the-Naze. It contains 

 Chalk pebbles, large flints, London clay septaria, and Crag sand, 

 and is full of mammalian bones. In hard specimens it could not be 

 distinguished from the older Boulder-clay. 



I have not a sufficiently minute acquaintance with the neighbour- 

 ^ Geol. Mag., Vol. III. p. 348, map. 



