462 NOTES ON THE ABERCROMBIE CAVES, 



From the large Arcli or Tunnel, several smaller caverns branch 

 off, which I had not time to examine closely. One of these is 

 entered from the east side and near the upper entrance to the 

 Archway : after a few yards it divides into several passages which 

 a little further in are found filled up with red earth containing 

 fragments and logs of wood. But this red earth is perforated in 

 all directions with the burrows made by wombats. These animals 

 still inhabit this cave, but by what way they enter it is not known ; 

 for it is impossible thaithey could climb the rocks or enter by the 

 passage we did, so that they must have some entrance from the 

 side of the valley, which it would be important to discover. I 

 have no doubt that some fossil bones might be found in this red 

 earth deposit, which I purpose shortly to examine. There is a 

 small but interesting stalagmite in this cave ; it stands in three 

 tiers with fluted sides. 



We can only arrive at the geological age of these caves from a 

 consideration of the formation of the physical features of the 

 surrounding country. To quote from my former notes on this 

 district, the general geological features of this country consists of 

 Silurian shales, sandstones, conglomerates, and limestones, with 

 occasional intrusive masses of greenstone trap, and at Mulgunnia 

 the estate of Mr. Warden T. Smith, P.M., near the Grove Creek, 

 there is a small outcrop of granite, covering these rocks are 

 patches of pliocene tertiary rounded quartz pebble drift, overlaid 

 by basalt. These patches of drift are the remnants of the beds of 

 those ancient watercourses, which in Pliocene times drained the 

 surface of this country. Streams of lava from volcanoes now 

 extinct, flowed into the old valleys, burying the water-channels, 

 subsequently long continued denudation eroded fresh channels 

 through these rocks, deepened the valleys, and thus gradually 

 formed the present physical features. 



Now the bed of Grove Creek is several hundred feet below the 

 level of the old Pliocene channel ; so that we may form some 

 conception of the enormous time, that must have elapsed since 



