60 Geological Society: the Rev. W. B. Clarke 



and sandstone, with subordinate beds of lignite, which extends from 

 the Hunter river southwards towards Brisbane Water. The lignite 

 constitutes the so-called Australian coal. This formation, owing to 

 its beds along the shores of the inlet being placed horizontally, and 

 being divided by nearly vertical joints, gives rise to regular lines of 

 coast, both in a longitudinal and transverse direction. It forms 

 along the coast a high range, which, except at the entrance, divides 

 the lake from the sea. Within the lake a series of extensive bays, 

 bounded to the water's edge by steep cliffs, run out like fingers, 

 far up into the country. The water of the inlet is for the most 

 part very deep. 



On the western side of the lake, and nearly opposite its sea- 

 entrance, a promontory, bounded on either side by a bay, is formed 

 by the Tirabeenba mountain, which stretches from the S.E. to the 

 N.W., and in the latter direction ends abruptly in a lofty but not 

 very precipitous escarpment : this sudden termination is occasioned 

 by a fault. This mountain range then turns to the W., and after- 

 wards to the S.W. ; between it and the next range a wide valley 

 intervenes. 



The north-eastern flank of the north-western extremity of this 

 range swells out into a hill of low elevation, from the base of which 

 to the water's edge a low flat extends ; the flat is about fifty yards 

 broad, and is, in point of level, within a foot of the surface of the 

 water ; it continues along the base of the slope for the space of about 

 half a mile : it is called by the aborigines Kurrur-kurran. To the 

 south and west of this flat the slopes of the mountain come down to 

 the margin of the lake. The surface of the flat is composed of black 

 sandy vegetable mould, and of detritus thickly interspersed with the 

 roots of plants and grasses; trees of large growth, which are prin- 

 cipally Eucalypti and Casuarinae, together with some others of smaller 

 dimensions, stand at intervals upon it, and grow even close to 

 the water. Beneath the alluvial matter the rock occurs in situ : this 

 is a sandstone, which is for the most part of a compact and semi- 

 crystalline texture, approaching to chert ; its strata run out to some , 

 distance, at a small depth below the surface of the water, and render 

 the lake in that part very shallow. 



Throughout the whole of the alluvial flat, stumps and stools of 

 fossilized trees are seen standing out of the ground, and one can 

 form no better notion of their aspect, than by imagining what the 

 appearance of the existing living forest would be if the trees 

 were all cut down to a certain level. In the lake also, where it ad- 

 joins the flat, to the distance of from 80 to 200 feet from the shore, 

 numerous points are seen, like -those of a reef of rocks, just peeping 

 above the surface of the water ; these points are the fossilized stools 

 and stumps of tree, similar to those which are found on shore. The 

 greater part of these stems, both of those on land and in water, stand 

 vertically ; many of those on shore have remains of their roots in the 

 sandstone rock beneath the alluvial matter ; and of those which stand 

 in the water, one at the distance of three feet from the shore has 

 portions of its roots imbedded in the sandstone on which it rests. 



