Deposits, Limestone Creek 13 



percolation of acicl-laden waters from the interior — i.e., as the 

 main channels became choked up by the accumulation of 

 debris, silt, and gravels, etc., the rushing waters caused by an 

 annual flood would endeavour to find a passage along the 

 lines of joint or shrinkage. At present the water traverses 

 from A to B (see plan), and from B finds its way 

 through narrow or flattened orifices to lower levels, re- 

 entering the Limestone Creek about 200 yards below 

 the entrance to the cave. The roof of the entrance, and for 

 some distance inward (about 20 feet), consists of a mass of 

 whitish marble beautifully scalloped by the action of running 

 water. The entrance is very nearly on a level with the 

 Limestone Creek, from which it is distant about 70 feet^ 

 and separated by the alluvium and an accumulation of 

 debris (see plan). After the first 33 feet are traversed 

 the narrow entrance passage gives place to a large chamber, 

 from which start various ramifying passages. Those through 

 which the water runs are narrower than that which I have 

 shown traverse lines. The floors of 2 to 3, 4 to 5, and 7 to 

 8 are simply masses of soft and hardening silt with, in some 

 places, stalagmital covering. These present many favour- 

 able spots for fossil hunting, but owing to the limited time 

 at my disposal I could not undertake any examination. 

 However, the plans and sections submitted may prove useful 

 as a basis for further examination by any one disposed 

 to undertake such interesting work. Many of the roof 

 fissures extend almost up to the surface of the deposits, 

 quite 60 feet in some places, and their sides are frequently 

 covered with stalactical drapery of every conceivable sbape 

 and of very beautiful appearance. The rate of accumulation 

 of these stalactites depends, apparently, on two principal 

 causes — viz., the quantity of percolating water holding car- 

 bonate of lime in solution, and the rate of evaporation of the 

 carbonic acid from the surface of each drop of water, the 

 latter depending upon the temperature, accessibility of the 

 air, and other conditions. During my last visit to Pender- 

 gast's Cave, No. 1 (there had previously been a rather heavy 

 rainfall), the stalactites were covered at their extremities 

 with bright, clear drops of water, some indeed were dripping, 

 and there was also a visible increase in the quantity of 

 matter I have denominated calcareous froth. It is probable, 

 therefore, that the rate of stalactital growth depends largely 

 on the seasons, a wet season being most favourable. The 

 lines of bedding are well seen in the interior of the cave,. 



