80 



KEPORT — 1873. 



Observation on the Rate at which Stalarjmite is heing accumulated in the 

 Inglehorough Cave*. By W. Boyd Davvkins, M.A., F.R.8., F.G.S. 



The only attempt to measure with accuracy the rate of the accumulation of 

 stalagmite in caverns in this country, is that made by Mr. James Farrer in the 

 lugliTborough Cave, in the years 1839 and 1845, and published by Professor 

 Phillips in ' The Rivers, Mountains, and Sea Coast of Yorkshire ' (second edition, 

 18-55, pp. 34, 35). The stalagmite, called " the Jockey Cap," rises from a crystal- 

 line pavement to a height of about 2^ feet, and is the result of the deposit of 

 carbonate of lime. 



For the sake of ensuring accuracy, three holes were bored at the base of the 

 stalagmite, and three gauges of brass wire (gilt) inserted, to mark the points where 

 the measurements were taken. 



The following is an abstract of the Table of measurements : — 



The only possible ground of error is the erosion of the general surface of the 

 solid limestone, of which the roof is composed, by carbonic acid, since the year 

 1845 ; and this is so small as to be practically inappreciable. There is therefore 

 evidence that the " Jockey Cap '" is growing at the rate of •204() of an inch per 

 aimum, and that, if the present rate of growth be continued, it will finally arrive at 

 the roof in about 295 years. This comparatively short lapse of time will probably 

 be diminished by the' growth of a pendent stalactite above, that is now being 

 formed in place of that which measured 10 inches in 1845, and has since been 

 accidentally destroyed. It is very possible that the " Jockey Cap " may be the 

 result, not of the continuous, but of the intermittent drip of water containing a 

 variable quantity of carbonate of lime, and, therefore, that the present rate of growth 

 is not a measure" of its past or future condition. All the stalagmites and stalactites 

 in the Inglehorough Gave, at this rate, may not be older than the time of Edward 

 in. From this it follows tliat the thickness of layers of stalagmite cannot be used 

 as an argument iu support of the remote age of the strata which they cover in the 

 caverns, such as Kent's Hole and Bruniquel. At the rate of a quarter of an inch 

 per annum, 20 feet of stalagmite might be formed in 1000 years. 



Note on the Stump-Gross Caverns at Greenhow near Pately Bridge. 



By J. W. Ellis. 

 These caverns were discovered in 1860 by miners who were searching for lead, 

 and who cut into them at a depth of 9 fathoms from the surface. The paper gave 

 a description of the caverns, which are chiefly remarkable for the great beauty of 

 the stalactites which they contain. 



The Round Boidder Hills of Craven. By W. Gomeesall. 



The author described some hills of Boulder-clay which lie between the rivers 

 Aire and Ribble ; their elevation, aljove the base on which they stand, varies 

 from 100 to 300 feet. The highest hills are to the north and west of the group, 

 whilst they gradually diminish in size to the south and east. The author supposed 

 the Boulder-clay to have been brought by icebergs, and deposited in what was then 

 a ba^' of the sea. 



* See Proc. of Manchester Lit. and Phil. Sec. Feb. 1873. 



