250 W. H. HmUeston — Cretchharrow in Purheck. 



Situated on the very top of Creechbavrow this section is very 

 suggestive. That the summit has been artificially flattened for the 

 purpose of supporting a structure is evident. At what period this 

 was first of all done it is impossible to say, but we are justified in 

 supposing that before human interference with such a prominent 

 feature of the landscape, tlie limestone rock stood out like a needle 

 or tooth above the encompassing greensward. Being too precipitous- 

 in its natural state to support a building, masses of the original 

 summit have been cut away and used in forming the strange medley 

 of rubble which is seen on the right of the section. We perceive 

 indeed the very fragments of limestone that have been detached so 

 as to make a platform on which to l)uild. The foundations are thus 

 partly natural and partly artificial. 



It is possible from specimens obtained in this pit more especially 

 to form some estimate of the cliaracter of this limestone. I hope to 

 treat the subject more fully witli appropriate illustrations in the 

 Proceedings of the Dorset Field Club. Meantime, the following 

 rough lithoiogical notes extracted from my field notebook will serve 

 to give an idea of some of the specimens. 



2a. This is a large fragment of creamy white tufaceous limestone 

 with specs and threads of oxide of manganese in places ; flattened 

 pisolitic bodies in brownish calcite are numerous. There are casts 

 of interiors of a shell not unlike Paladina. The whole of this 

 fragment has a tufaceous aspect and is free from the buff-coloured 

 patches which characterize a certain group of specimens. 



The external surface is rough and in one corner full of curious 

 shapes, which are probably concretionary bodies developed by 

 weathering. 



26. A white tufaceous limestone similar to the last. This is 

 pretty full of pisolitic bodies in brown calcite ; it moreover contains 

 a peculiar horse-shoe section in brown calcite, of which there are 

 indications in so many of the specimens. There are indications of 

 a Paludina likewise, but so merged in the matrix as to be indistinct. 



2d. Similar to the last and containing the indications of a Paludina 

 which clearly differs from the ordinary Purbeck species (P. carinifera 

 and P. elongata). 



3a. A creamy tufaceous limestone with some buff-coloured patches 

 and specs and threads of manganese oxide. Sections of ordinary 

 pisolites here and there. But this specimen is remarkable for three 

 very large horse-shoe sections, which certainly represent concretions 

 in brown calcite, whose origin is by no means clear. These sections 

 show a series of concentric rings with a large hollow in the centre 

 filled with the ordinary matrix. There is no radial structure ; one 

 end of the circle is thick, whilst the opposite end thins almost to 

 disappearance. Some of these horse-shoe sections are nearly 1\ inches 

 in diameter. 



3c. Eathei' more compact limestone with some buff markings. 

 The chief interest of this specimen is, that it seems to afford a solution 

 of the problem of the horse-shoe sections. There is to be seen here 

 a pisolitic concretion with an interior Wee a very small egg, of which. 



