SCIENTIFIC NEWS. 77 



From this it appears, that the tubes have hitherto been found 

 only in a single hill of drift sand on the sea-shore, of the ex- 

 tent of about five acres. The entire form of the tubes is not 

 known ; for they are discovered in consequence of being laid 

 bare by the drifting of the sand j and the same cause almost 

 always breaks off, and injures their upper extremity. The 

 manner in which they terminate below, is still less known : 

 one of the tubes was exposed by hazardous digging, in running 

 sand, to the depth of about fifteen feet, without the least ap- 

 pearance of its being about to terminate. They lie parallel to 

 each other, and nearly vertical, but at unequal distances — the 

 number must be very considerable, Mr. Irton having himself 

 taken away, at different times, not less than a hundred. 



The tubes, when first dug out, are very flexible, but exposure 

 to the air for a fqvv seconds deprives them of this quality. The 

 unctuosity of the internal glazing of these tubes, when re- 

 cently dug up, stated by Mr. Irton, in his first letter on the 

 authority of another person, appears, on more accurate exami- 

 nation, to be a mistake. 



A communication from George Cumberland, Esq., relative 

 to some limestone strata in the neighbourhood of Bristol, 

 was read. 



The strata here described compose the rocks opposite to the 

 Hotwell Walks, and are farther illustrated by two drawings ; 

 the one of the external face of the rocks, the other of a large 

 cavern recently discovered. In clearing the ground for the 

 erection of houses opposite to the Old York hotel, on Clifton 

 downs, some interesting varieties of sulphate of strontian were 

 met with, but the place being now covered with building and 

 garden grounds, there is little likelihood of its being soon again 

 opened to the researches of the mineralogist. 



A communication, accompanied by three drawings in illus- 

 tration, from Dr. Mac Culloch, Mem. G. S. relative to a re- 

 markable interrupted vein in lime -stone, was read. 



This vein occurs in a mill-stone which was shipped from 

 Limerick, and is at present at the royal powder mills at Wa!- 

 tham Abbey. The stone itself is a dark blue slaty limestone, 

 containing comminuted fragments of marine remains; the yeiu 

 by which it is traversed is whjtish compact carbonate of lime. 

 This vein, in its present state, consists of a number of separate 



.angular 



