Fossil Fish in Rocks of the Mansfield District. 5 



feet down to the river flats below, and forming the upper 

 ledge of this embankment, and immediately below the 

 surface, a band of hard rock four feet in thickness, which 

 has served to protect the underlying beds from denudation, 

 and has thus played an important part in determining the 

 present conformation of the hill. Looking north-east, the 

 hill rises before us in a plane, closely parallel to the plane of 

 stratification of this band. If we now walk along the 

 embankment with the hill on our left, we gradually come 

 down to the level of the river, and obtain evidences of its 

 action. Som6 of the rocks have been undermined by the 

 flood waters, and stand out in bold projections ; others lie 

 with their upper surface exposed in large flags, which 

 occasionally show ripple-markings, and an innumerable 

 number of what seem to be fucoids or the castings of worms. 

 As we come round the hill, and approach the point, No. 9, 

 where the line Z Z^^ crosses the river, the rocks form its bed 

 for a short reach, and pass out of sight on the other side. 

 Beds, superior to any now remaining on this hill, have been 

 revealed by the flood waters on the other side of the river ; 

 while a little to the east of this line, clear evidence exists 

 that the river has cut for itself a considerable depth and 

 width through the hard rocks into the softer rubbly shale or 

 mudstone. 



The general appearance of the locality favours the view, 

 that at no very distant period of time the flats above this 

 point were occupied by the waters of a lake, extending over 

 the Tannery Paddock and beyond. These flats are in winter 

 almost a swamp, and where it is cut by the river, I found 

 that the alluvial deposits attain a depth of some twenty feet. 

 The erosion of the hard rocks at this lower extremity has, I 

 think, di'ained the lake. 



Continuinsc on the north side of the river, along the 

 embankment, which now becomes more steep with the 

 projecting rocks shelving out, several lower beds show 

 themselves along the escarpment, marked No. 8. A short 

 distance from here, the embankment ceases to be precipitous, 

 and slopes out a long way to the flats. On reaching the point 

 marked Z'^ the aneroid indicated one hundred and forty feet 

 above the river. Hence, to the point of commencement, the 

 north sides of this isolated remnant of what was once an 

 extensive plateau, stretch away to the lower land. A survey of 

 the country ai'ound, from the highest part of this hill, gives 

 evidence of its former continuity with several other elevations 



