330 president's ADDRESS. 



very curious and beautiful effect. Eather more than half-way 

 from Hawes to Muker by the road up Fossdale Beck, and about 

 three-quarters of a mile on the Muker side of the division of 

 the watershed of Swaledale from that of Wensleydale, are the 

 " Buttertubs," nearly 1600 feet above sea level. I am indebted 

 to Mr. Faraday Spence, who was of the party, for the following 

 description of and remarks upon these remarkable chasms, as 

 also for the list of the plants observed by him growing within 

 them. 



"The 'Buttertubs' are on each side of and close to the road 

 from Hawes to Muker, and are perpendicular holes in the lime- 

 stone ; the larger from ten to sixty feet in diameter, and from 

 twenty to fifty feet deep. Some of the smaller are one to two 

 feet diameter, and apparently fifty or sixty feet deep at least. 

 Small trees and brushwood are found in the larger, and ferns are 

 luxuriant in all. 



"The theory that these are 'pot-holes' seems disproved by 

 the fact that there is none of the roundness, smoothness, or hori- 

 zontal marking, characteristic of pot-holes, produced by the 

 grinding action of water carrying stones or sand, and swirling 

 round and round. On the contrary there are innumerable verti- 

 cal grooves, from one to two inches wide, separated by sharp 

 edges; and from the sides project portions of rock, thin and 

 knife-like at the top, gradually thickening to near the bottom, 

 and then quickly tapering to a blunt point. These, in some 

 places, resemble an armoury full of ancient weapons, halberds, 

 swords, spearheads, and axes, all point upwards, growing out of 

 the rocky walls. 



" This formation and the vertical grooving are evidently 

 caused by rain-water trickling down, and dissolving the lime- 

 stone as it passes over the surface. 



" The top of the limestone is covered by a bed about one foot 

 thick of porous rock, quite crumbling where exposed. It is 

 identical in appearance with the overlying peat, where that has 

 been similarly exposed to the weather. It suggests that an 

 ancient bed of peat has been petrified, and is now being disin- 

 tegrated by solution of the limestone deposited in it." 



