TET7NKS IN QUATEENARY SANDS AT READING. 



305 



slope, of which the base was prolonged horizontally under the re- 

 constructed bed (as seen in our pit), gently rising to the south as it 

 approached the cliff. Fig. 2 is a section of the probable transitional 

 line with the beds north and south of it. Such a line would be 

 reached if the east face were exposed up to the south face. The 

 line of junction is dotted in ; for its exact direction can, of course, 

 only be surmised. The irregularity in the junction between the 

 unaltered and reconstructed beds, as shown by the latter extending 

 further south at the west side of the pit, is only to be expected 

 when it is remembered that the transitional line represents the 

 sinuous margin of a river, and any little bay indenting the bank 

 would carry the reconstruction into the concavity. 



The relation of all these beds exposed in the pit to the whole 

 south slope of the river-valley is well seen by ascending the incline 

 to the limits of the Eedlands estate (south). The arrangement is 

 shown in a diagram in fig. 3 ; and the outcrop of the beds there 



Fig. 3. — Diagrammatic Section of South Bank of River-valley. 

 (Slope greatly exaggerated, rise 79 feet in about 1 mile.) 



N. S. 



Reconstructed — 

 Claya. Sands. 



River River 

 Thames. Kennet. 



a. Alluvial plain. 



b. River-graTel. 



c. High-level gravel. 



d. Basement beds of London- 



clay. 



e. Mottled clays. "] 



/, Buff sands. I Woolwich and 



g. Leaf-beds. I Beading Series, 



h. Greeu flints. J 



i. Chalk. 



drawn can be verified quite satisfactorily. The gravel-bed (A in 

 fig. 1) is seen to belong to the general system of the river-gravels. 



South of the pit, ascending the slope, these gravels thin off and 

 leave the mottled clay exposed at the surface ; higher up these beds 

 are covered by the basement beds of the London Clay, which were 

 well exposed in digging the foundation of a house near the top of 

 the slope. The basement beds are again capped, at the summit 

 (79 feet above the river), by the entirely unstratified, unfossiliferous, 

 high-level gravels, consisting of a large proportion of rounded quart- 

 zite masses and subangular flints. 



Thus the south slope of the river-valley at the Eedlands estate, 

 affords a very perfect example of a typical valley-slope, and in ad- 

 dition presents the more exceptional aj)pearances of the reconstruc- 

 tion of the Tertiary beds by fluviatile agency, in such a manner that 

 the easily removable elements of the latter remain, though altered 

 in structure and intermixed with the organic and inorganic remains 

 of very different ages and widely diverse conditions. And the sec- 



