636 REPORT — 1891. 



map, Sheet 15, will show that the Gault was supposed to thin out and disappear 

 near Shaftesbury, so as to allow the Upper Greensand to rest directly on the 

 Kimmeridge Clay. This proves to be a mistake ; the Gault is continuous into and 

 beyond the valley of the Stour. Moreover two miles south of Shaftesbury a tract 

 of sand emerges from beneath the Gault, and forms a terrace which for a little 

 distance has a separate escarpment of its own. 



Near Bedchester this tract of sand is nearly half a mile wide, and thence it can 

 be traced to Child Okeford, on the eastern side of the Stour valley, its length being 

 between four and five miles. 



Exposures near Bedchester show that it consists chiefly of quartz sand contain- 

 ing a variable amount of giauconite, some beds being yellow and consisting chiefly 

 of quartz, others being grey or dark green and containing a large amount of 

 giauconite. There is also a bed of greenish-black glauconitic clay, 2J feet thick, 

 consisting of dark purple clay and minute grains of dark green giauconite inti- 

 mately mixed together. Most of the sand is of fine grain, but there are some thin 

 layers of coarse sand. 



So far as is yet known, and with the exception of a small exposure near Lul- 

 worth Cove, this is the most westerly tract of Lower Greensand in lilngland. 



8. On the Continuity oj the Kellaways Beds over extended areas 'near Bedford, 

 and on the Extension of the Fuller's Earth Worlcs at Wohtirn. By 

 A. C. G. Cameron. 



[Communicated by permission of the Director-General of the Geological Survey.] 



In this paper further evidence is submitted from diflerent parts of the country, 

 of the continuity over extended areas of the Kellaways Rock above the Lower 

 Oxford Clay. Several fine excavations, the result of railway enterprise, have 

 afforded sections of these beds in places where their presence was only inferred 

 before. More than the usual thickness is indicated by records recently obtained 

 from deep sinkings and borings in the Midland districts, especiallv the Bletchley 

 boring of 1886-7. 



The extraordinary concretionary stones, noticed in Wiltshire by Smith as 

 characterising this formation, and quarried away years ago at Kellaways for road- 

 Stone, jut out in the Valley of the Churn, near Cirencester, and stand about in 

 clusters in the Valley of the Ouse at Bedford like gigantic fungi. The plane of 

 separation of the Upper Oxford and the Kellaways in Bedfordshire is formed by a 

 shelly calcareous band in contact with a shelly cap to the concretionary stones. 

 Where this plane is a broken one there is no development of concreted rock, and 

 the lowest sediment of Upper Oxford clay is loamy, passing down into Kellaways 

 sand. Above the calcareous band there is sometimes an indurated seam of sandy 

 marl, breaking into conical forms ; the product, apparently, of stalactitic infiltration. 

 Pits are opened at the outcrop of the Kellaways (a persistent stratum in the Ouse 

 Valley) and are carried down through the Lower Oxford (selenite clay), Cornbrash 

 and Cornbrash clay to Great Oolite limestone, which is quarried for lime-burning ; 

 the ' lam earth,' the loamy portion of the Kellaways, being mixed in the mill with 

 the Lower Oxford, which is dug for brickmaking. Excellent sections, showing 

 the above series, are to be seen. 



Observations on the extension of the Fuller's Earth Works at Woburn Sands, 

 ■with some description of the beds, are given, and the mining industry now springing 

 up is commented on. 



