a 
214 A. G. HAMILTON. 
“ Here in Australia we may observe the surface as nature has 
formed it. The aborigines have not spoiled it nor improved it, 
nor scarcely at all altered it, but where the cattle of the settler 
cross a well-grassed slope in any part which is naturally moist, 
immediate changes are effected. The surface waters begin their 
work at some small hole made by the hoof of an ox, and gradually 
enlarge and deepen it, (always working backward towards the 
hill) until a dry channel several feet in depth is excavated. In 
this way thousands of cubic feet of soil are carried into the low- 
lying valleys by streams in places where for ages there has been 
no current or denudation.” 
‘“‘ Large swamps which in the memory of settlers have been dry 
lands for several years in succession, have by tillage and drainage 
of the adjacent slopes, been converted into lakes which have in a 
brief period increased in depth and area, and inundated large 
tracts of fertile land. Lake Learmonth, Lake Burrambeet, and 
notably Lake Modewarre are notable instances of this kind of 
action.”* 
Any one familiar with sheep runs in hilly country will remem- 
ber the net work of paths on the hillsides ; and by the formation 
of these tracks, drainage is largely affected. Cattle do even more 
damage in this respect, and many landslips occurring on steep 
hillsides can be seen to have had asa starting point a cattle track. 
There is a very curious damage done by cows to the surface on the 
steep slopes of the Illawarra Range. Along the hillsides are to 
be seen tracks composed of alternate grassed lumps and hollows 
between, bare of grass, and in wet weather full of mud. They 
look like the impression of a huge cog-wheel on the soil, and where 
they go directly down the hill form regular flights of steps. I can- 
not say with certainty how they are formed, but believe that the 
cows all tread on the same spot day after day and so cut the 
hollows. These hollows, small as they are, are often the origin of 
landslips ; besides which they invariably hold water a consider- 
able time after rain, and become centres of little colonies of rushes 
and sedges which soon begin to spread over the pasture. 
* Op. cit., p. 206. 
