On the Vitreous Ttibcs found near Drlgg^ in Cumberland. 529 



an attempt to recover it, the sand fell in and prevented further in- 

 vestigation. The lowest part of the last piece, that was detached, 

 was not closed, and did not exhibit any peculiarity of structure, 

 from which it could be inferred that the extremity had been reached. 

 The tube appears to have tapered in its descent, its diameter at the 

 'bottom of the excavation being reduced to half an inch. One spe- 

 cimen in the collection of the Society is bi-furcated ; whence it is 

 probable, that the stem was divided into two branches, one of which 

 may have escaped observation. Small lateral branches proceeded 

 from different parts of the stem, not exceeding two or three inches 

 in length, nor a quarter of an inch in diameter at the points of 

 insertion. They were conical, and ended in points, gradually 

 bending downwards. Internally they were hollow, and opened 

 into the principal duct, which, except in dimensions, they perfectly 

 resembled. 



The outside of the tube is coated with an agglutinated sand, which 

 viewed with a lens is found to consist of black and opaque white 

 grains mixed together, and rounded, as if by incipient fusion; the 

 white grains, when farthest from the centre of the tube, having a 

 reddish tint. The stem is irregularly angular, like a vegetable stalk 

 much contracted by drying, and is rugged with deep longitudinal 

 interrupted furrows, like the bark of the elm or of the cork tree. 

 The sides of the tube are about the twentieth part of an inch thick, 

 and are very hard and rigid. 



On proceeding inwards, their substance gradually loses the appear- 

 .ince of sand, and becomes vitreous, the whole interior being covered 

 with a smooth glaze. This vitrified matter is whitish or limpid, 

 containing specks of a dark olive colour and a few air blebs. It is 

 sufficiently hard to scratch glass. 



The irregular form of the interior surface corresponds to that of 



Vol. II. 3 X 



