CHESIL BEACH AND FLEET MEETING. Ixv. 



THE GEOLOGY OF THE DISTRICT. 



Leaving the little village of Langton the party crossed the 

 fields to the coastguard station, a distance of a mile and a- 

 quarter, profiting on the way by the guidance of Mr. Hudleston, 

 the eminent geologist, and Mr. Bowles Barrett, the first 

 authority on the botany of the district. Going down into a 

 small quarry Mr. Hudleston showed his followers a typical 

 section of the Forest Marble, the characteristic of which is a 

 number of false-bedded lime-stones, not true stratigraphically, 

 but dipping into a mass of clay. On reaching the Fleet, Mr. 

 Hudleston, standing on the top of the great oyster bank of the 

 Fuller's Earth formation which projects into the Fleet, addressed 

 the members as follows : 



I consider that this would be the most appropriate place for making a few 

 remarks on the geology of the immediate district. The President pointed out 

 last year at Osmington the important feature of the great anticlinal known as 

 the Weymouth Saddle. The party are now standing on the very axis of that 

 saddle, since from the Fuller's Earth, which you see in front of you, the several 

 formations which constitute the Weymouth triangle dip away from this dome on 

 either side. The existence of the Fuller's Earth at this particular spot was first 

 discovered by Damon, the well-known geologist of Weymouth. Though it 

 attains its maximum development of 150 feet in the West of Dorset, the formation 

 was first named Fuller's Earth more than 100 years ago from its containing in 

 the neighbourhood of Bath the material known as Fuller's earth, which from its 

 property of absorbing grease was used by clothmakers in the operation of 

 " fulling." It is essentially a marine formation, and in some places contains 

 ammonites, though not here. Clays are the predominant feature, and this great 

 clay formation may be traced northwards through the Cotteswolds, thinning all 

 the way until it appears to merge in the Stonesfield-slate of Oxfordshire. In this 

 district the Fuller's Earth is characterised by thick banks of oysters such as the 

 one we are now inspecting. This is not a mere shell-drift, but rather represents 

 an oyster-bank, such as occurs in water several fathoms deep of existing seas. 

 The particular oyster which makes up this bank is a very narrow form, less 

 curved on the whole than the typical Ostrea acimtinata to which it is referred. 

 Specimens with both valves in apposition are abundant and well preserved, and 

 the variety of form is very considerable, some specimens being modified by 

 attachment. The next formation in order of time to which the programme 

 alludes is the Forest Marble, and here again we meet with an anomaly in 

 geological nomenclature so far as this district is concerned, for there is no forest 

 here, neither is there any marble in the quarries. The Forest Marble of Dorset, 

 which is probably about 120 feet thick at its maximum, is very clayey and marly, 



