Tooth -vi(u-l:^ of Thylacoleo. 95 



After washing away the lighter clayey material, the residue — 

 of which there was a fair quantity — -consisted for the most part 

 of quartz. By the naked eye a few black and bright-green 

 particles could be picked out of the clay, and both these 

 showed, the latter very sparingly, in the residues after wash- 

 ing. Among the black particles some were transparent and 

 brown under the microscope, and could be referred to augite. 

 Most of them, however, were quite opaque, with dull surface 

 and glassy fracture. These appear to be a variety of spinel, 

 probably pleonaste, and not picotite, as no chromium was 

 detected. The bright-green particles are, no doubt, chrome- 

 diopside, a mineral associated with the granular olivine, occur- 

 ring as nuclei of volcanic bombs and as ejected blocks round 

 some of our newer crater hills. Colourless zircons and a few 

 grains of yellowish olivine are also present. The red patches 

 found at a depth of about three feet or more in this clay have 

 apparently been enriched in their iron contents by the leach- 

 ing of the upper part of the bed, and the iron so introduced 

 has taken the form of minute concretionary pellets of limonite. 

 The general character of the clay and its contained minerals 

 point strongly to it being a volcanic tuff, in all probability laid 

 down on the tertiary rocks before the subsidence took place 

 Avhich created the depression now occupied by swamp lands. 



The bones found at Pejark Marsh are, as mentioned, almost 

 entirely of a fragmentary nature, only three or four toe bones 

 being complete. They occurred principally just at the base of 

 the black clay where it merges into the yellow clay below, while a 

 few, but always very small in size, were scattered higher up in 

 the former, a fact proving that they must have sunk through 

 that part of the old swamp soil formed before the time of their 

 deposition. 



We were at first, more especially perhaps as the aboriginal 

 implement was of the nature of an anvil or pounding stone, 

 disposed to attribute to human agency the fragmentary con- 

 dition of the bones forwarded by Mr. Merry ; but further con- 

 sideration and the securing of a larger collection have caused 

 us to modify this opinion. We also thought that the place 

 where the bones and implement were found was. probably once 

 the site of a camp by the side of a lagoon or miarsh, but our 



