68 A. C. G. Cameron — Kellaicays Beds near Bedford. 



sections have, however, a direct bearing on the concretionary origin 

 of these stones, as set forth by Prof. Harker, that is not mentioned 

 in his paper. The Upper Oxford and Kellaways beds in the Bedford 

 sections are divided by a shelly calcareous band in contact with a 

 slielly cap to the concretionary stones. Where this line is a broken 

 one, there is no development of concreted rock below, and by 

 gradations the Oxford Clay passes into silt and sand, seeming!}'- 

 indicating the piling up of the shells at j^articular spots as would 

 happen on a shore exposed to strong currents ; the subsequent 

 decomposition of the animals resulting in the sand beneath being 

 concreted into hard rock, as Prof. Harker says. The sand seems 

 to have had deep water over it, as there do not appear to be any 

 fossils whatever in it. On the other hand, the concretionary stones 

 are — externally anyway, as Mr. Smith says, " congeries of organic 

 remains." 



All the animals, except the Belemnites, seem to have died 

 young; Serpula, so conspicuous on other Oolite shells, are entirely 

 wanting. There are shelly bands wholly made up of Belemnites 

 and Grypliaa, while Ammonites, Aviculce, and other forms besides, 

 adhere to the upper surface of the doggers in great profusion. 

 Pieces of this rock are more like Kentish rag than an}' other stone 

 I know. A variety of Gryplicea dilatata occurs in such abundance 

 and so like Gryplic^a incurva in the Lias, that one would think the 

 destruction of these beds could have conti-ibuted shells of Gryphwa 

 to the Drift, as easily as the Lias. Although a hard rock when dug 

 at any depth, the Kellaways becomes rapidly friable and crumbles 

 on exposure ; and where these stones jut out naturally, the shelly 

 cap is usually gone. 



There is an indurated seam of sandy marl above the shelly band 

 at Oakley, which breaks into conical form,«, exhibiting the structure 

 known as cone-in-cone. The broad surfaces of these cones are 

 upwards, ending against the Oxford Clay. 



I saw no instance of the apices pointing towards each other ; and 

 the whole series stand vertical in the stratification with the points 

 downwards, or to the bottom of the seam. It is difficult, therefore, 

 to conceive of these cones being due to the upward escape of gases 

 — as suggested by Mr. John Young of Glasgow,' although these 

 would be emitted ; the decay of the dead animals being sufficient 

 to generate gases in the deposit whilst the bed was in process of 

 formation. 



Throughout this seam the texture of the stone is more or less 

 fibrous, and in the phenomena of the cones the fibres seem united 

 into tufts, which taper downwards and end in a point ; rather 

 resembling some stalactitic infiltrations. 



The tract of land occupied by the outcrop of the different 

 Kenawa3's beds, although of necessity only a narrow band, presents 

 changes in the character of the soil marked enough to be known by 

 distinct local names. 



' Geol. Mag. Yol. II. June, 1885, on Cone-in-Cone Structure. Abstract of 

 paper read to Geol. Soc. Glasgow. 



