SUMMARY AND CONCLUSIONS. 
(1.) The Swan and Helena Rivers Lave recorded four cycles 
of erosion, which are marked by river terraces. The first 
cycle was one of stillstand in the Guildford District. 
The second, third, and fourth cycles were caused by re- 
juvenating movements, indicating an uplift of the land 
or a sinking of sea-level of 22 feet. 
(2.) The climate of the district was warmer before the move- 
ment than it is now. This is indicated by two important 
formations, the older Perth Shell Banks, and the younger 
Rottnest Shell Banks. 
(3.) The amount of movement is the same as that described 
as being due to “uplift” in the Perth District (23 feet). 
(4.) Various physiographic features in the Perth District, at 
Rottnest Island, in the Bunbury-Mandurah District, and 
in the Darling Range east of Perth can be correlated 
easily with the four cycles of erosion, which may there- 
fore be taken as the local basis for the subdivision of 
Recent Time. 
(5.) In Pre-Guildford time actual subsidence was taking place 
in the Swan River District, while uplift was in progress 
further south in the Bunbury-Mandurah District. 
(6.) The evidence of recent changes in the Swan River District 
supports Daly’s hypothesis of a recent world-wide sink- 
ing of ocean level. 
In collaborating on this paper we desire to state that the fol- 
lowing partition of work was made. The theodolite levelling and 
construction of the profiles were carried out by E. A. Budge, and the 
general field work and correlation were done by M. Aurousseau. We 
also wish to thank our students Messrs. C alder and Thorburn, of 
the Guildford Grammar School, and Messrs. Cummins and Worboys, 
of the University of W ester# Australia, for assistance in the field 
work. 
