73 



NOTICE OF SOME FOSSILS EECENTLT DIS- 

 COVERED NEAE EISDON, TASMANIA. By M. 



Allport. 



As I ptrrpoae forwarding the interesting fossils which I have 

 now the honor to submit for the inspection of the Fellows of 

 the Royal Society to Professor Owen by the next mail, I avail 

 myself of this opportunity to record their discovery, and to 

 give a brief account of the locality and formation in which 

 they were found. 



For many years past Limestone has been quarried from a 

 bed of Travertine at Geilstown Bay, a deep inlet on the 

 eastern bank of the River Derwent, about a mile below 

 Risdon Ferry. The hills lying between Risdon and this 

 quarry are of the poor white Mudstone found over so large 

 a portion of Tasmania, and which is associated with the 

 Carboniferous, or Mountain Limestone. The Mudstone in 

 this locality contains vast numbers of shell casts belonging to 

 the genera Spirifer, Productus, and other characteristic fossils 

 of the Mount Wellington Limestone. As no trace is now left 

 in the Mudstone of the Carbonate of Lime which must at one 

 time have filled these casts, the probability is that the lime 

 has been, in the course of ages, carried off by the percolation 

 of rain water, or other water containing carbonic acid, through 

 the Mudstone, and has gone to form the bed of Travertine 

 referred to in a deep pool on the course of some former rivulet, 

 or the lime may have been derived from some more distant 

 bed of the Mountain Limestone. 



The Geilstown Travertine is highly fossiliferous, containing 

 many interesting animal and vegetable remains, which afford 

 some clue to its geologiccil age ; of these remains those 

 belonging to the vegetable kingdom are by far the most 

 numerous, the impressions of many of the leaves being 

 especially beautiful. It is a matter of great difficulty to fix 

 the species or even genera of plants from the mere, impressions 

 of seed vessels, leaves, and stem^, and it therefore behoves 

 the observer to examine carefully a very large number of 

 specimens befoie any such attempt can be made. For twelve 

 years past I have collected specimens from this quarry, and 

 have in that period discovered the impressions of two seed 

 vessels which I am unable to assign to any existing Tasmanian 

 form. Impressions of the stems and leaves of some plant 

 closely resembling a species of Leucopogon (a heath-like 

 plant, now common on the hills in the immediate neighbor- 

 hood of the quarry) are very abundant. Impressions are also 

 numerous of serrated leaves bearing a superficial resemblance 



