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junction owing to the natiu'e of the overlying beds is difficult to 

 make out. A steep scramble up the sandy slope having been with 

 difficulty in some instances overcome, the town of Old Swindon 

 was traversed and the chief object of the day attained, as the mem- 

 bers threaded their way through debris and building stones to the 

 sunny corner of a large quarry on the top of the hill, whence the 

 chief building stone of the neighbourhood is obtained. Whilst 

 Mr. Moore was collecting his treasures around him the Secretary 

 took the opportunity of alluding to some of the physical characters 

 of the country which they had traversed since leaving Bath ; " how 

 they had crossed over in an ascending order the east edge of the 

 Somersetshu'e Coal basin from the Liassic valley of Bath, over the 

 succeeding members of the Lower, Middle, and Upper Oolites, how 

 the three great limestone escarpments of Inferior Oolite, Corallian, 

 and Portlandian beds were successively boimded at then- base by 

 the Lias, Oxford, and Kimmeridge clays, and how they now stood 

 on the topmost beds of the Jurassic series wliich Mr. Moore had 

 so carefully studied and was now about to describe." By this time 

 Mr. Moore was quite ready to resume his subject, and from a 

 rostrum of Portland sand, Avith the fine section of Portland and 

 Purbeck beds in front, described each bed one by one. The base, 

 he said, consisted of a bed full of Trigmias, Perna and Cardium 

 some 2ft. thick ; to this succeeded some 30 feet of concretionary 

 sandstones or impui'e gritty limestones between beds of sand, 

 these latter prevailed more at the base of the quarry. On the 

 top of these beds which contained marine organisms came some 

 10 feet of chalky looking limestones, which represented the Pur- 

 beck beds, so remarkable for the fresh water fauna which they 

 contain. Some darkish bands near the top of the quarry were 

 pointed out as similar to the " dirt beds " of the coast, and as 

 containing a most cxirious series of marine and fresh water 

 organisms. From those beds Mr. Moore had been sufficiently 

 fortunate to make an addition of 80 species to the small number 

 liitherto obtained, and amongst these eight or ten species of 



