10 DILUVIAL REMAINS. 



manifest by a magnifier. The stop in the progress 

 of the work is even visible ; soft; stony matter 

 having arisen from one of the tubes, and be- 

 come indurated there in a convex form ; in others 

 the creatures have perished, but their forms or 

 moulds remain, though obscure, yet sufficiently 

 perfect to manifest the fact ; these tubes, by expo- 

 sure to the air for any length of time, have the 

 internal or softer parts decomposed, and the stone 

 becomes cellular. A. (Plate 1, fig. 1) represents 

 an enlarged fragment of the down limestone, with 

 the mouths of the cells ; B. C. D. are the appear- 

 ance of some of them, with the forms of the insect 

 which constructed them ; E. represents the stony 

 matter by which the work is continued fixed at the 

 mouth of the cell ; Fig. 2, the same when decom- 

 posed, the animal matter having quite perished in 

 some cases, and partially in others ; Fig. 3, en- 

 larged. This stone burns to a fine white lime, and is 

 very free from impurities, containing in a hundred 

 parts 



Carbonate of lime ... 88 



Magnesia . v . 8 



Silex ..... 1 



Alumine*, coloured with iron . ,3 



Too 



Another quarry presents, likewise, unquestion- 

 able evidence of animal origin, veins of it being 



* I have called this alumine, stained with oxide of iron ; but it 

 seems more like vegetable or animal remains, adhering to the filter 

 like a fine peaty deposit, and is lost in combustion. 



