100 SECTION AT ONE TREE POINT, 



Pw.S. TAS. 



plies to the worked up leaf beds. I shall have to deal 

 with this feature presently. The southern portion appears 

 to be more regular. Under a thick layer of Basalt which, 

 rapidly thins out in northern direction follows a layer of 

 vesicular Basalt, which rests on altered leaf beds, of con- 

 spicuous yellow colour, of about 3 to 4 feet in thickness; 

 below these are the normal leaf beds which g-et rather 

 arenaceous towards the base, resting on Breccia of gi'eat 

 thickness- 



These leaf beds are again observed at sea level, abo<ut 

 40 to 50 feet below the main section, overlaid by massive 

 Basalt, which is divided by a vesicular band (6). 



4. Description of the Strata Observed. 

 A. The Breccia. (PI. v. and vi.) 



Mr. R. M. Johnston has given a most accurate de- 

 scription of this very rock, whose peculiar features he 

 well noticed. It is "a motley assortment of coarse and 

 huge angular blocks principally of the fossiliferous mud- 

 stone." This feature is exceedingly well shown in Plate vi. 



Though without doubt the blocks of mudstone form 

 far the majority, there occur many boulders of Diabase 

 frequently of large dimensions (See Plate v.). These 

 boulders are always well rounded, and thus sharply con- 

 trast with the angular blocks of mudstone. The boulders 

 are imbedded in an argillaceous, somewhat gritty matrix. 

 At the northern portion a mudstone boulder of fairly 

 large size is deeply pressed into the underlying leaf beds. 

 (See Plate vi.). The dark lines of stratification seen in 

 the white leaf beds closely follow the contour of tJie 

 boulder, and this proves conclusively that it must have 

 pressed into the leaf beds while these were still in a 

 plastic state. 



I have been greatly puzzled as to the origin of this 

 Breccia. It unquestionably closely resembles a moraine 

 produced by the action of glaciers, and I think that under 

 other circumstances nobody would hesitate to consider it 

 of glacial origin. On the other hand, no scratched 

 boulders have so far been found, and I cannot quite 

 imagine how a glacier could have passed over bods 

 which were unquestionably in a soft and pliable state (7) 



(6) To judge from Mr. Johnston's figures th^i Breccia could be 

 observed at sea-level in 1881. During my visits the Breccia was not 

 visible, being covered under a layer of debris. 



(7) Unless they were frozen hard. 



