170 The Geology of the Berks S^ Hants Extension, 



On the north side of the Railway, at the west end of the cutting 

 at Crofton Engine, a curious deposit was removed, of which there 

 was a good section in the old road leading to Freewarren. It 

 was apparently stratified, and contained bones, teeth, or horns of ox, 

 sheep, pig, badger, and red deer ; with fragments of British and 

 Roman pottery, calcined flints, and an abundance of land shells, 

 especially of Cyclostoma elegans. Some of this deposit may still be 

 seen near the canal Feeder. 



At about a quarter of a mile from Savernake 

 Station, the Upper-green-sand is reached, and the 

 beds cut through between this point and the Station, 

 yielded many sponges. The most common form 

 is that shewn in fig. 1. It is an undescribed 

 species allied to Siphonia, the oscules radiating from 

 the central cavity outwards. Another species found 

 here is somewhat similar in shape but quite dif- 

 Fig. 1. ferent in structure, having tubules running up the 



stem and opening into the cavity and on the outside. Sponges which 

 appear to be of the same species as the latter, sometimes approximate 

 closely in form to Chenenodopora undulata of Michelin ' plate 40., 

 fig. 2., (Polypothecia undulata of Benett). Jerea elongata (Michelin 

 plate 39, fig. 4«), Jerea pyriformis (Michelin plate, 36, fig. 3), t/er^o 

 excavata (Michelin plate 33, fig. 3., plate 39, fig. 2), and Jerea 

 gregaria {Polyjwthecia grcgaria of Benett), were also more or 

 less common. A few specimens of Syphonia pyriformis and 

 HalUrhoa costata occurred, and others which in the present confused 

 nomenclature of fossil sponges, it is useless to attempt to specify 

 unless a figure can be referred to. 



The sponges seemed to be most plentiful at from 25 to 30 feet 

 below the top of the Upper-green-sand, and to the westward of the 

 station very few occurred. 



Near the east end of the Canal Tunnel, at about the level of the 



sponges, the scapulae with some ribs and vertebrae of a Plesiosaurus 



were found. It is remarkable that among the ribs were six or 



seven grey quartzose pebbles, varying from half an inch to an inch 



* Michelin Iconographie Zoophytologique. 



