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THE GEOLOGIST. 



Nicholson's part for attempting to bore for tlie precious fuel ; but whether 

 this gentleman had not gone low enough, or that the coal-seams had cropped 

 or thinned out here, in their dii'ection from the north, we cannot say. 



We next were invited to cast our eyes to Hambleton Hill, then we should 

 behold an object called the " White Mare." Scarcely knowing the meanmg of 

 this phrase, but domg as requested, we were astonished to observe at a distance 

 of twelve or fifteen miles a faithful representation of a white horse shaped out 

 of the rock on the steep hill of Hambleton. This large hieroglyphic, the size 

 of which I do not at present know, was executed a few years ago through the 

 instrumentality of a party of gentlemen, as I understood, who came from York. 

 This object is a great curiosity, and may be seen at the station at Pilmoor by 

 travellers along the Malton and Thirsk railway. — Yours truly, Robt. Mortimer, 

 Eimber, Malton. 



Geology of Readixg. — Dear Sir,— Your correspondent, A. H., should 

 get Mr. Prestvdch's pamphlet, "The Ground Beneath Us," Van Yoorst, Lon- 

 don, 18S7, for a general account of the Lower Tertiary beds and the gravels. 

 Eor a special account of the geology of the neighbourhood of Reading, I beg- 

 to refer him to the recently published Geological Survey Map of that part (sheet 

 13), and to a memoir, now in the press, illustrating that map. The following 

 information may be useful to your correspondent : 



The beds in the neighbourhood of Reading are, in ascending order. Upper 

 Chalk (with flints), Woolwich and Reading beds (the Thanet sands being 

 absent), London Clay, and Drift-gravel. 



No doubt fossils may be got in many of the chalk-pits, but I did not look 

 for theni myself. In the railway-cutting at Pangbourn the characteristic fossils 

 of the Chalk occur, and in a chalk-pit by the river side a small reversed fault 

 may be seen. 



The Woolwich and Reading beds are almost unfossiliferous in the western 

 part of the London basin. The "bottom-bed" of this formation, however, 

 contains in this neighl^ourhood a few fossils in the state of casts, besides the 

 well-known " oyster-bed" that generally occurs immediately above the Chalk. 

 The " bottom-bed" consists of roughly-laminated dark grey clay and clayey 

 sand, generally with green grains — often, indeed, being a regular greensand. 

 The oidy place that I know of where this bed is now to be seen at Readmg is 

 at Castle Kiln, where there is the following general section : — 



Plastic clays and sands of the Woolwich and Reading beds, over thirty feet. 



Bottom-bed of the Woolwich and Reading beds, over four feet. 



Chalk, with fossils. 



Li the bottom-bed here the following fossils were found by Mr. Gibbs, the 

 fossil-collector of the Survey, and myself : Pish-teeth, Area, Nucida, Cardium 

 Laiffoiii, Ci/rena tellineUa, Psammobia ?, and a small Bri/ozoan. All were casts, 

 ratlicr imperfect, and, though tolerably plentiful, not to be foimd without a 

 little practice. The bed of oyster-s hells I did not find here ; but there are 

 most likely casts of oyster-shells in the bottom-bed ; neither was the upper- 

 most part of the Chalk riddled with the network of tubular cavities (made by 

 boring molluscs) so often to be seen in it where capped by the "bottom-bed." 



In a brick-yard about half a mile to the north-east of Theale the " bottom- 

 bed" may again be seen ; here it is thicker, and also contains casts of shells. 

 Various species of oysters are the only fossils hitherto published as found in 

 these beds in this district. 1 believe that the ofiicers of the Geological Survey 

 were the first to find any others. 



Tlicrc are sections of the " basement -bed" of the London Clay at Kates- 

 grove Kiln (at tlic top of the section), and at the brick-yard about half a mile 

 to the north-west of Upper Early; and when I was first at Reading it migiit 

 be seen at the brick-yard near Redlands. It has been found at some depth at 



