55 



been due to the peculiar state or composition of the agglo- 

 merate when deposited in the waters of the lake. 



Altered Claystone. 



The claystone, a specimen of which has been sent for 

 inspection, has evidently been metamorphosed by contact 

 with the older basalt, for in a section upon the Launceston 

 and Western Eailway at Hunter's Mill, Perth, the very same 

 claystone is shown to be of considerable thickness. It presents 

 the appearance of abaked pipeclay, being exteriorly of a whitish 

 colour, and breaking readily into small hardened cubes. 

 When most distant from the underlying basalt, it is soft and 

 friable and internally white ; it becomes more hardened as it 

 approaches the igneous rock, until finally at point of contact 

 it is metamorphosed into a dark close grained crystalline 

 chert, which no longer splits into cubes, but has a smooth 

 conchoidal fracture ; portions now in my possession have 

 extremely sharp edges, very hard, and from descriptions 

 given of native implements. I think it probable that they 

 were manufactured by clippings from this material. I have 

 been informed that this point was a favourite haunt of the 

 aboriginal tribes — hence the name Native Point, given to 

 Mr. Gibson's estate near to it. 



The metamorphosed claystone again occurs overlying the 

 same rock in a cutting of the St. Leonard's road, leading to the 

 railway station, close to Mr. Westbrook's house. The top 

 surface is frequently polished, and vertically, it often takes a 

 prismatic form. 



Stevenson's Bend. 



Leaving the Corra Lynn agglomerates — of which I hope 

 soon to be able to say something more — I come to the 

 exposed section at Stevenson's Bend. I have already 

 spoken of the richness of the fossil leaf impressions at this 

 point. At low water are to be found numerous hardened 

 ferrugineous nodules, which have been washed by the River 

 Tamar from an overhanging band of brecciated nodule^, 

 mixed with siliceous pebbles. Most of the concretions are 

 replete with casts of the elm-like leaf figured (1) in my former 

 communication, with here and there the impress of an imbri- 

 cated pine twig, or some strange fossil nut. Sometimes a 

 lucky stroke of the hammer discloses the perfect impression of 

 a new leaf form, a portion of the frond of an unknown fern 

 with its furcate venation, or perhaps the well-defined impres- 

 sion of the bark of some ancient type of tree. All this can be 

 dryly communicated on paper, but only the brethren of the 

 hammer, or those who take a livelv interest in the evolution 



