corresponds to this level, and at Albion Town there is a terrace 
greatly dissected by ox-bows, standing live feet below the West 
Midland level. Other features to he considered render it extremely 
probable that a line level exists in Ibis position, arid that, we are 
not dealing with accidental terraces. We have named the fourth 
level the Helena Level, When the width of the present Valleys is 
considered, the presence of clear and continuous records of the 
Helena and Wesl Midland levels is seen to be impossible. The Swan 
now meanders in a. valley as wide as that of the Guildford days. 
The lowest level is that of lie present flood plums. At Guild- 
ford the present, (loo I plain of the Swan is 13 feet below the West 
Midland level. At Albion Town the distance has not increased, hut 
at Upper Swan it rises to IS feet. The depth of the Helena flood 
plain below the West Midland level is IS feet in the western profile 
and 11 feet in the eastern, the distance between the two being only 
half a mile. In both cases it is well above the flood plain of the 
Swan, indicating the steeper gradient of the Helena.. 
The significant inference from the foregoing details is that the 
total intervals due to rejuvenation (Guildford to present levels) in 
both rivers in the Guildford District are of the same order, that is, 
about 22 feet, as indicated by the profiles. Now, as a corollary to 
the previous rule, we stale that the ini err als belireen river terraces 
due solely to rejuvenating movements will be equal to the actual 
amount of displacement only in the vicinity of base-level. But the 
maximum “uplift/* recorded by Somerville is 23 feet (16). We con- 
clude, therefore, that the river record of the Guildford District is an 
actual measure of the rejuvenating movement, and that Guildford 
was near base-level. Jutson states correctly (9) that the Swum is 
affected by the tides as far as Guildford at the presold day. 
The levels should prove useful in t lie study of rates of erosion 
if Daly’s hypothesis he proved ultimately to he correct, as the ter- 
races are dissected by innumerable brooks the ages of which can be 
gauged accurately. Sub-surface drainage (11) was observed at 
Upper Swan. 
Notes on the Profiles . — Profile No. 1 shows the Cn versharn, 
Guildford, West Midland, and Present levels in the Swan valley, the 
West Midland level being here slightly truncated. Guildford itself 
is on a remnant of the (hwersh am- Guild ford slope. In the Helena 
Valley the Caversliam, West Midland, Helena, and Present levels are 
shown. Profile No. 2 shows the same levels as No. 1 for the Swan, 
the West Midland level being again truncated. In the Helena, the 
Guildford, West Midland, and Present levels appear. Both of these 
profiles were brought into line with survey datum by tying the 
traverse on to a railway bench mark. Profile No. 3 (near Albion 
Town) shows an encroachment dune on the west, and the Oaversham, 
