98 



Much of the soil from this portion, upon immersion in water separates 

 into a fine, almost impalpable, sediment, which readily permits the 

 extraction of the imbedded shells, free from stain and fracture, in the same 

 degree of perfection as those from the well-known Pleistocene freshwater 

 beds, at Grays, in Essex, from which indeed, if mingled with them, they 

 could not be distinguished. 



The upper portion of the bed cannot be separated by its organic 

 contents from that which we have just described, but uj^on its surface 

 becomes lighter in colour, from the greater admixture of calcareous 

 matter, which hardens upon exposure into a lighter-coloured spongy-looking 

 substance, resembling the Tufa formed in the neighbouring streams, 

 indicating the probable exhaustion of the clays, upon which the water 

 action which formed it had been exercised, and the consequent, though 

 less considerable, coi-responding action upon the calcareous beds below 

 them. The significance of these observations can only be appreciated 

 when connected with circumstances to be mentioned hereafter. No trace 

 of water- course or ancient pond exists near the spot, and we know 

 that the streams of all the valleys immediately around us have 

 their sources in the waters collected by the Fullers-earth bed first 

 mentioned, precisely as those of the upper or North Eastern portion of 

 the valley where this does not occur, originate in the clays of the Upper 

 Lias, where they crop out upon those slopes of the Cotteswolds, the 

 water-shed of which finds its way to the Severn. 



It is difficult to imagine that the recent deposit co\ild have been 

 formed since the bed upon which it reposes assumed its present angle 

 of inclination towards the valley, as its tliickness at the point of section 

 proves that its outward extension must have been considerable. As we 

 know that no trace of it is found uj^on the summit of the hill, which is 

 occupied by a gi'eat Oolite bed, stratigraphically higher than that which 

 supports it, dipping moreover at an angle of two degrees only towards 

 the E.S.E., we may be satisfied that it never existed there, and can extend 

 inwards or upwards but to a small distance, easily estimated, were it of 

 any importance in answering the questions which naturally suggest 

 themselves, viz. : when, and under what circumstances, was it formed, 

 and were its margins swept away 1 



"We have only to glance at the two outer headlands of the inlet, to be 

 reminded that the great valley upon which we look down, is entirely one 

 of denudation, and that the space between us and heights of the same 

 level, was once occupied by continuations of the hUl-masses upon which 

 we stand, as far, at least, as the older hills wlaich form its opposite 

 boundary ; we have to consider, therefore, in the changes of surface 



