PLEISTOCENE AND RECEN'r STRA~D MOVEMENTS
PLEISTOCENE AND
RECENT
STRAND
MOVEMENTS
13
IN
SOUTHERN NATAL.*
By T. J. D. Fair, M.A.
[PLATE
II.]
ABSTRAOT.
Within recent time l evidence of negative eustatic shifts of sea level is forthcoming
from a study of the South African coastline. These strandline movements are studied
with reference to the Southern Natal coast, the main line of investigation being that
of the river profiles and associated river terraces.
OONTENTS.
Page.
13
INTRODUCTION
SECTION I-OOASTAL EVIDENCE
A.
B.
O.
Raised beaches and rock-cut platforms
River mouths
Summary of evidence ..
14
15
15
SECTION 11.-STREAM PROFILE EVIDENCE
A.
B.
O.
D.
E.
Introduction
River profiles achieved
Graphical projection of profiles
Theoretical considerations
Summary of evidence
SECTION Ill-OONCLUSION
ACKNOWLEDGMENTS
BIBLIOGRAPHY
16
16
17
18
21
22
22
22
INTRODUOTION.
A. V. Krige (1927) has to a great extent borne out R. A. Daly's supposition
of a 20 feet negative eustatic shift of sea-level within recent time. The present
thesis attempts to supplement Krige's work with a fuller study of the coastline
of Southern Natal. As strand movements are best shown on the coast, coastal
evidence is examined first, that is, the data obtained from raised beaches, rockcut benches and river mouths. Devolving from a possible negative shift of sealevel are the effects upon the stream courses. Thus, Section II deals with the
longitudinal and transverse profiles of the rivers of Southern Natal with a view
to discovering knickpoints and terraces indicative of an earlier higher stand
of the sea.
A. V. Krige has shown that a double emergence has occurred within recent
time. First a " major" emergence of 40 to 100 feet, followed by a " minor"
emergence of 15 to 25 feet. It is with these movements of the strand-line that
the present paper is concern~d.
Prior to these movements the coastline was elevated, producing a plain
" fringing the Natal coast below a height of approximately 500 feet" (King,
*Natal University Oollege.
Geomorphologic Studies, No. 10.
14
TRANSACTIONS OF THE GEOLOGICAL SOCIETY OF SOUTH AFRICA
1941, p. 225). This was followed by a submergence of 150 to 200 feet, supposedly
due to glacio-eustatism, but owing to its comparatively rapid succession it
caused no more than a deepening of water offshore and a silting up of the
entrenched river valleys produced by the previous emergence. The coastline
retained its remarkable straightness, therefore, but at the same time displayed
phenomena resulting from the submergence. The later" major" and" minor"
emergences did not in any way change the general character of the coastline,
though important topographical features resulted. Thus, the shoreline of
Southern Natal is a compound shoreline (Johnson, 1919, p. 190) and, as it is not
mature when referred to both its emergent and jts submergent characteristics,
it is a submature compound shoreline. A. V. Krige (1927, p. 10) styles it, " A
young to mature coastline of submergence appreciably modified by later emergence phenomena." A shoreline is classified primarily according to its most
recent relation to sea-level, but as the earlier emergence still exerts a powerful
influence upon its character it is more correctly a compound shoreline than a
shoreline of submergence.
Characteristic of the Natal South Coast are the almost unbroken sandy
beach, the prolific grass and bush-covered dunes and the rarity of bold rockheadlands. The dunes form part of a narrow terrace (A. V. Krige, 1927, pp. 9,
64) that flanks practically the entire length of the coast. In turn this terrace is
backed by a ridge of red sand (L. J. Krige"April, 1932, pp. 55-57) averaging 200
feet above sea level, a feature characteristic of the south-east and eastern coasts
of Africa. All the river mouths are either partially or completely blocked by
southward deflected baymouth bars.
SECTION I.-COASTAL EVIDENCE.
A. Raised Beaches and Rock-cut Platforms.-Wa ve-cut ledges are poorly
developed along the Natal South Coast due to the fact that all formations dip
appreciably seaward (Thompson, 1942, p. 46), and for the most part are
obliterated by the thick covering of grass- and bush-covered dunes. Where
found, however, they are cut across the dipping strata of Ecca and Table
Mountain sandstones and are not purely structural features. It is at many of the
river mouths that these benches are best seen, for the rivers are migrating southwards, thus removing much of the covering sand and revealing the platforms
in section through down-cutting consequent upon the lowering of base-level.
Railway cuttings, too, have laid bare these platforms.
The narrow terrace fringing the coast is both an erosional, i.e., rock-cut,
and a built feature. There is little doubt that it represents the "minor"
emergence, though in certain localities it is abnormally high due to the accumulation of wind-blown sand and to the down-wash of red sand from the hillside
back of it. Where it is definitely established as an erosional feature, its height
above mean sea level varies between 20 and 30 feet, and the thin soil mantle
supports stunted vegetation and grass. Where it is a built feature, however,
it is as much as 50 feet above mean sea level, as at Umgababa and Umtentweni, *
and the greater depth of soil has allowed the growth of fairly dense bush.
* For positions of places and rivers referred to in the text, see the topographic map
issued by the Irrigation Department (Sheet 2).
PLEISTOCENE AND RECENT STRAND MOVEMENTS
"15
B. River Mouths.-There is little doubt that the present baymouth bars
and spits which occur at the mouths of all the southern Natal rivers, were formed
subsequently to the submergence of 150 to 200 feet. As this submergence preceded the " major" and "minor" emergences, there is the strong possibility
that baymouth bars and spits existed prior to these last emergences. Thus,
there is every right to expect, in theory at least, that raised baymouth bars
and spits exist and are indicative of these suggested recent changes of sea-level.
Though the present longshore current along this section of the coast is to the
north, eddy currents (Johnson, 1919) have built up the present southward
deflected baymouth bars and spits. This southerly deflection has been in existence
some little time, for data from borings obtained from the South African Railways and Harbours indicate that the rock bottoms of the present alluviumfilled estuaries slope northwards. Further, there is generally a lack of rock
outcrops for some distance north of the present outlets, and the great majority
of rivers have undercut rock-banks at the south side of their mouths.
Evidence of raised baymouth bars and spits is forthcoming from the
following rivers :-Ingane, Amahlongwa, Inkombana, Umhlungwa, Umzimai 2
and Injambili rivers, for each is deflected southwards by a baymouth bar built
up at the present time and by an older feature, a dune-ridge (the possible raised
spit), which is an extension of the narrow terrace referred to. These dune-ridges
vary in length from 500 yards in the case of the Amahlongwa river to about
200 yards in the case of the Umzimai 2 and Injambili rivers. They are thickly
covered with vegetation and are remarkably straight, having a uniform width of
some 500 feet and a height of 20 feet. Where undercut they reveal white and discoloured beach sand. No rock outcrops occur seaward of these ridges and their
characteristic position of stretching across the mouths of the broad alluviumfilled estuaries can be appreciated.
Their uniform height and their relation to the fringing terrace and rock-cut
platforms referred to strongly suggest their being the result of an emergence of
about 20 feet. With this emergence these bars were soon covered with vegetation,
and the continuance of the southerly deflected current enabled them to be
preserved.
The Umgababa river dune-ridge or raised spit is, however, deflected northwards. This is probably related to the northward deflected Bluff spit (L. J.
Krige, April, 1932). The river is at present deflected southwards like the others,
however, and is in process of destroying this raised spit. It is a significant fact
that these raised spits are absent at the mouths of the larger rivers such as, the
Umkomaas, Umzimkulu and Umtamvuna rivers.
C. Summary of Evidence.-The evidence from coastal features includes
rock-cut benches, raised beaches and raised baymouth bars or spits. The data
considered most reliable are tabulated below.
The evidence strongly favours an eustatic fall of 20 to 25 feet, comparable
with A. V. Krige's " minor" emergence. There is a significant break at 15 to
16 feet above mean sea-level, and A. V. Krige (1927) and L. J. Krige (1932)
refer to a halting stage during this final emergence represented by a platform
12 to 14 feet above mean sea level.
16
TRANSACTIONS OF THE GEOLOGICAL SOCIETY OF SOUTH AFRICA
Evidence in favour of a " major" emergence from the Natal South Ooast
is very scattered and this cannot be definitely established with reference to this
section of the coastline alone. More reliable is the evidence discussed in Section
II in connection with this emergence.
Topographical
Features.
Locality.
Umbogintwini R.
Amanzimtoti
Winkle Spruit ..
Umgababa
Renishaw
Amahlongwa R.
Scottburgh
Park Rynie
Umdoni Park
Inkombana R.
Turton ..
Umhlungwa R ...
Umzimai 2 R.
Umzimai 2 R . . .
Injambili R.
Indomba R.
U mhlangangkulu R.
Umtentweni R.
Umtentweni
Uvongo ..
Port Edward
Port Edward
Elevation above
Mean
S.L.
Feet.
Feet.
19
Bench
25-30
Bench
Line of boulders
16
Bench and beach deposits
25
Beach conglomerate
20
Raised spit
20
Bench
20
Rock-cut terrace
16
Bench
20
Shell bed
32
Terrace
20
Raised baymouth bar
20
Raised baymouth bar
25
Bench
20
Raised spit
20
Bench
18
Bench
15
Bench
20
Line of boulders
20
Terrace
16 and 20
Bench
20
Terrace
80
45
50-70
50
50
60-70
SECTION n.-STREAM PROFILE EVIDENCE.
A. Introduction.-The method of reconstructing the river profile to
ascertain the stages of its evolution has been fully dealt with by Baulig (1935).
The method has been adopted here in essentially a local sense with a view to
finding knickpoints and river terraces related to the" major" and" minor"
emergences. Thus the method of thalweg reconstruction is applied to the rivers
in their lowest reaches. The present study is virtually the investigation of the
statement by King (1941, p. 228) that" knickpoints associated with the latter
(Le., the" major" and" minor" emergences) are possibly present in some of
the coastal streams." This local and limited use of the method has been
employed by Hanson-Lowe (1938) in connection with the Ohannel Isles.
The coastal rivers and streams are entrenched and emerge from gorges
200 feet and more deep, flaring out into alluvium-filled estuaries with spurs and
valley-sides dipping steeply into the alluvium. At the same time, however,
" none of the rivers have wide floodplains in their lower reaches corresponding
to existing base-level" (King, 1941, p. 230). There are, as a result, two immediate
considerations involved in the application of the" thalweg" method to the
southern Natal rivers. The first is the great depth of alluvium and the total
unreliability of the preservation of knickpoints in such a medium, and secondly,
the steep gradients of the tributaries feeding the main streams.
B. River Profiles Achieved.-A " dumpy" level and levelling staff were
used in determining the profiles of the thalwegs. This was inevitable' in the
absence of large-scale contour maps. The dense bush and reed-filled lagoons
limited somewhat the scope of the study. All heights were referred to high tide,
PLEISTOCENE AND RECENT STRAND MOVEMENTS
17
as it was found that the level of the water surface in lagoons, completely blocked
by bars, was practically the same as the water level of rivers, open to the sea,
impounded at high tide.
The lagoon character of the lower reaches of the rivers certainly affects the
normal profile, but it would seem that this same condition would have existed
during possible higher stands of sea-level within recent time, especially as the
150 to 200 feet submergence played as important a part/then, as it does now, in
determining the presence of sand-bars and alluvium-filled estuaries.
In all, twelve longitudinal profiles of main streams and tributaries were
obtained extending from the Amanzimtoti River southwards to the Inkombana
river, a distance of about fifty miles. Terraces flanking rivers, however, were
measured by means of an Abney level over a greater length of coastline and in
those places where" levelling" was impossible due to bush and undergrowth.
The profile of only one large river was determined, that of the Umpambinyoni
river, and from experiment it was seen that the possibility of finding knickpoints
in other large rivers was nil, due to the depth of alluvium and the well-graded
profiles of these rivers in their lower reaches. Thus attention was paid to
tributaries and to smaller streams flowing directly to the sea. Wooldridge and
Kirkcaldy (1936) emphasize the fuller record of the denudation chronology
being preserved in tributary valleys.
O. Graphical Projection of Profiles.-The ideal manner in which to project
profiles is to correlate longitudinal and transverse profiles, so that terrace heights
may fix points on the destroyed part of the profile. The rarity of well-preserved
paired terraces makes such a correlation almost impossihle on the Natal South
Coast rivers on account of the youth of the streams and the almost complete
absence of a regular series of rock-cut terraces.
Themain criticisms of Johnson (1938) concerning the extrapolation of profiles briefly refer to the projection, not of a straight line, but of a constantly
varying curve, to the fact that this profile, now destroyed in its lower parts,
was not necessarily a uniformly decreasing slope, and that the present preserved
graded stretch has not necessarily maintained the same gradient since sea-level
fell or the land rose. Further, he says, " when the length of the restored profile is
measured in miles, and the change in sea-level position merely in some few
scores or few hundreds of feet, it is evident that an almost imperceptible change
in rate of the projected curvature must lead to highly significant changes in the
position of sea-level thus determined." These criticisms have been replied to by
Baulig (1940) with varying success. Their application to the rivers studied here
is not wholly justified for conditions are different, though other difficulties do
enter. First, the majority of the rivers studied are young and while admitting
that the present graded stretches have possibly changed their gradients during
the past, it does not really matter whether the destroyed profiles had a comparatively uniform or an ungraded slope, as they are not of any great length, a
few hundred feet in many cases. Further, as the changes of base-level here being
investigated occurred in recent times it is not likely that the waves of headward
erosion have proceeded far. Thus, the distance that profiles have to be extrapolated is not great. In fact, the projected profile is in some cases practically a
straight line and not a constantly varying curve.
18
TRANSACTIONS OF THE · GEOL·OGICAL SOCIETY OF SOUTH AFRICA
D. Theoretical Considerations.-The application of the principles of the
method to the rivers of southern Natal necessitates the consideration of the
history of change of base-level during Pleistocene and recent times. The most
important of these changes was the submergence of 150 to 200 feet. Its inception
affected river profiles to an enormous extent and, in spite of the later emergences,
it is the prime factor influencing river gradients in their lower reaches at the
present time. Its influence is such that the later emergences have left no record
of knickpoints in the larger river valleys . .
Suppose the later phases of strand-line history, as suggested by A. V. Krige,
be assumed and applied to river systems and let us note the changes of gradients
and the topographic features resulting therefrom.
~~:::-=:::~:::::::"'-==::-------""-'-------J50r-t.
:::::::::~:""::--=::-----------l/lO~t.
~-~>o....,,:;:-=~-----J85f...t.
1
----~----~8
f------FIG. 1.
Profile adjustments of a mature river to changes of base-level.
(1) Mature Rivers.-Fig. 1 represents a mature well-graded river profil~ of
any of the larger Natal South Ooast rivers. .AB is the profile subsequent to the
300 feet emergence. With a rise of sea-level of sO:gle 150 feet, representing the
submergence, the shoreline is carried from B to X. Immediately the river will
begin to build a delta into its drowned estuary and, as it does so, aggradation
will proceed slowly upstream, thus constructing the profile 1-1. The rate of
growth of the delta, while depending upon the size of the river and the load
carried, will hardly be such that the whole estuary will become completely filled
with alluvium prior to the later emergences of approximately 40 feet (" major"
emergence) and 20 feet (" minor" emergence). Thus, with the eustatic fall of
40 feet the river mouth will be carried seaward to Y, still within the estuary.
Rejuvenation sets in, and the river partially reduces the former delta, carries
this material further into the estuary and degradation upstream is reduced by the
growth of the new delta and by the still drowned character of the estuary.
Profile 2-2 results, merging gradually with the original profile AB.
The same conditions operate following the "minor" emergence, and
profile 3-3 comes about without any sharply defined knickpoint having been
formed in the rock-floored valley AB. This is due to the powerful influence
exerted by the earlier submergence. That the filling of the estuary with alluvium
PLEISTOCENE AND RECENT STRAND MOVEMENTS
19
has but recently been achieved may be judged from the fact that only now are
the rivers beginning to contribute silt to the ocean floor (A. V. Krige, 1927, p. 21).
There is, thus, an adjustment throughout the whole of the lower course of the
river to the negative shifts of sea-level. Therefore, apart from the Umpambinyoni river no further profiles of any large rivers were obtained, as the search
for knickpoints would have proved fruitless.
On the other hand, terraces are likely to have been formed indicatiye of the
higher stands of the sea. The differences in altitude of profiles 1-1, 2-2 and
3-3 strongly suggest this, but their constructional character, along with the
depth and narrowness of the river valleys, militates against their preservation
at the present time. Thus, while no terraces were observed within the valleys
themselves, that is, upstream from their estuaries, they were observed within the
estuaries themselves, their horizontal character here suggesting rather former
sea-levels than previous river profiles. Alluvial terraces, referable to the" minor"
emergence, were observed within the lower parts of many of the river estuaries;
but they are by no means extensiv-e. They are merely remnants of terraces
which by their very nature and composition have not been able to withstand
later erosion. The following rivers have easily recognisable terrace remnants,
referable to a higher stand of the sea :-Umlaas, Amanzimtoti, Illovo, Umzimbazi, Umgababa, Umkomaas, Umtwalumi and Umzumbi.
The preservation of these alluvial terraces is by no means guaranteed, however, for the large Umgeni river, at Durban, with a floodplain graded to present
base-level shows no terrace remnants at all.
Rock-cut terraces, however, may be formed as a result of the" major"
emergence especially, for waves and ripples were able to attack the estuary
sides at a time when it was not filled with alluvium. Thus, following upon this
first emergence, and as a result of subsequent piecemeal erosion, a series of
horizontal, accordant truncated spurs dipping into the alluvium may be expected.
Such rock-cut terraces, indicative of the" minor" emergence, are not so likely
to be found, as the estuary by then is practically completely filled with alluvium
and this acts as a protecting cover for the valley walls.
The best examples of these rock-cut terraces were found flanking the present
estuaries of the Umzimbazi, Umgababa and Umzumbi rivers. They show a
remarkab'le uniformity of height, being 70 to 90 feet above the floodplains of
their respective rivers. Further, their 'horizontality compares strikingly with
the rise behind them of the 500 feet coastal plain. They are rock-cut and are
found in areas of varying rock types, from Middle Ecca sandstone at Umgababa,
Table Mou'ntain sandstone at Ifafa, and granite at Umzumbi. Where fnsequents
have cut back into these terraces, breaks in slope correspond almost perfectly
with the general terrace level. The Umzumbi river displays best these relics of
the " major" emergence. They flank both sides of the river for a distance of
two miles from the mouth. Upstream from this point the river loses its estuarine
character, the terraces disappear, and the usual gorge-like features result.
Thus, changes of base-level will not be represented by knickpoints on the
larger rivers, but rather by terraces, rock-cut and alluvial, in the river estuaries.
20
TRANSACTIONS OF THE GEOLOGICAL SOCIETY OF SOUTH AFRICA
(2) Young Rivers.-Fig. 2 represents the profile of a young stream, ungraded
and with a steep gradient. It may be either a young stream flowing directly to
the sea, such as the Umzimai No.1, Inkombana, Park Rynie 1 and 2 streams, or
a tributary of a large mature river, provided that the tributary joined its parent
river below the highest point reached by the sea during the submergence. All
the tributaries here discussed are of this type.
:'?---.:::::::::::......:::::-----------------------,/SOfA.AJ..
:'S----:~"""""'==__------------~ /I 0 {.u.t
~~------------~g5r~
f-
-
FIG. 2.
Profile adjustments of a young river to
ch~nges
of base-level.
Let AB be the original thalweg. With the submergence, sea-level rises about
150 feet, and the mouth of the stream is carried from B to X, not as far as in the
case of a mature river. Immediately, the stream beings to contribute silt to its
newly formed estuary and aggradation proceeds upstream. This, however, is
limited by the ungraded nature of the river and cannot proceed further than
the nearest rapid, waterfall or excessively steep gradient. Thus, profile 1-1 is
instituted. With the" major" emergence and the drop of sea-level to Y, rejuvenation causes degradation which, here, is more active than aggradation owing
to the steep grade. While the delta grows, now at a lower level, and aggradation
upstream is overcome by degradation, the wave of headward erosion is brought
into contact with the original valley floor, and it proceeds to form a well-marked
knick, giving profile 2-2. Meanwhile, the delta grows, but owing to its smaller
extent and to the steeper grade of the river, at no time does aggradation supersede degradation.
The next movement, the" minor" emergence, causes the sea to retreat
to Z, the delta built at the higher base-level is destroyed and the wave of headward erosion attacks the valley floor argain, causing another knickpoint to proceed gradually upstream. Thus, the new profile will be 3-3, slight aggradation
having proceeded in the lowest reaches.
The prospect of finding terraces related to these knickpoints is not good,
as the valleys are too steep and have no well-developed floodplains. Thus, it
21
PLEISTOCENE AND RECENT STRAND MOVEMENTS
would seem that while knickpoints are best noted in the younger river valleys,
terraces indicative of the same falls of base-level are best seen in the valleys of
maturer rivers.
E. Summary of Evidence.-The evidence derived from knickpoints and
terraces may now be tabulated, and the following heights above sea-level
represent possible higher base-levels.
Previous base-levels obtained from knickpoints : R.Tributary B
C
D
"
E
"
UMZIMAI No.1 R.
UMPAMBINYONI
INKOMBANA
R.
Tributary
UMGABABA
65
45
23
Feet.
15
10
40
60
70
35
40
25
25
21
30
9
9
R.-
Tributary
Park Rynie Sp. 1
Park Rynie Sp. 2
65
60
42
30
25
15
10
15
Rock-cut terraces 70 to 90 feet : Umzimbazi, Umgababa, Umkomaas, Umtwalumi and Umzumbi Rivers.
Alluvial terraces 20 to 30 feet : Umlaas, Amanzimtoti, Illovo, Umzimbazi, Umgababa, Umkomaas, Umtwalumi
and Umzumbi Rivers.
The heights deduced from a study of river profiles are open to criticism
on the grounds that the streams, being young, have numerous breaks in slope,
many of them non-cyclic, and that the method of thalweg reconstruction used
here in a limited manner cannot employ every break in slope. This is true to a
certain extent, but from the study comes the fact that certain" bands" are
apparent within which the former base-level is located. As Baulig says, "the
reconstruction then takes the form, not of lines, but of bands within which the
true profiles are probably included."
From the heights obtained by the extrapolation of profiles it is seen that
there exist two clearly defined bands, one between 9 and 15 feet, and the second
between 21 and 30 feet. The other two groups are more doubtful, but in view of
the fact that corroborative evidence in favour of a previous base-level at 70 to
90 feet above present sea-level is forthcoming from a study of river terraces, then
the 60 to 75 feet band must be taken as being possibly more valid than the 35
to 45 feet band. This latter is a doubtful group, though it may correspond to a
35 feet terrace noted by certain investigators.
Alluvial terraces 12 to 14 feet above the norma} river levels are not everywhere indicative of a higher stand of sea-level, for they can easily have been built
during the present cycle in times of flood. On the other hand there are terraces
of the same height that can be related to former base-levels, for example, those
found in the broad valleys of the Amanzimtoti and Umzumbi rivers.
22
TRANSACTIONS OF THE GEOLOGICAL SOCIETY OF SOUTH AFRICA
SECTION IlL-CONCLUSION.
A final summary of data suggests the following elevations :Feet.
15-18
9-15
Coastal evidence
Stream profile evidence
River terrace evidence
Feet.
19-25
21-30
20-30
Feet.
50-70
60-75
70-90
The topography of the coastal region of southern Natal attests to a former
strand-line 20 to 30 feet above present base-level, with a halting stage during the
emergence now represented by knickpoints and benches. There is little doubt
that this emergence has been eustatic and took place within recent times. This
is shown by the still surviving remnants of alluvial terraces, by the almost
complete lack of grading in the young stream valleys to present base-level and
by the fact that there is no great development of floodplains related to present
base-level. On the other hand: benches are being cut by the sea at the present
time and the shoreline is being eroded back at a fairly rapid rate.
Coastal evidence in favour of the" major" emergence is far too incomplete
and scattered to warrant correlation, but the river terraces noted strongly
suggest such a former strandline 60 to 70 feet higher than at present.
Warping of the terraces related to the" minor" emergence subsequent to
their uplift is considered unlikely.
ACKNOWLEDGMENTS.
The writer here records his appreciation for the information given by the
South African Railways' Engineering Department, at Durban, in connection
with river mouths, and to Dr. L. C. King for very helpful discussions in connection with the investigation. Thanks are also due to Messrs. M. G. Marwick, A. T.
Druce and D. D. C. Plowes, who at various times accompanied me on excursions.
BIBLIOGRAPHY.
BAULlG, H. "The Changing Sea-level." Publ. 3, Inst. British Geographers, 1935.
" The Reconstruction of Stream Profiles." Jour. of Geomorphology, Feb. 1940. I
HANSON-LoWE, J.-" The Bearing of Morphological Data in the Channel Islands on the
Eustatic Theory." Jour. of Geomorphology, Vol. 1, No.2, 1.938.
JOHNSON, D. W.-Shore Processes and Shoreline Development. John Wiley and Sons,
1919.
Notes on J. Hanson-Lowe's " Bearing of Morphological Data." Jou,r. of Geomorphology, Vol. 1, No.2, 1938.
KING, L. C.-" Geomorphology of the Coastal Hinterland of Natal." Trans. Geol. Soc.
of S.A., Vol. XLIV, 1941.
KRIGE, A. V.-" An Examination of the Tertiary and Quaternary Changes of Sea-level in
South Mrica, with special stress on the Evidence in Favour of a Recent World-wide
Sinking of Ocean-level." Annals of Univ. of Stellenbosch, Vol. V, Section A, No.1,
1927.
KRIGE, L. J.-" The Geology of Durban." Trans. Geol. Soc. of S.A., Vol. XXXV, April,
1932.
THOMPSON, A. 0.-" The Coastal Terraces of Eastern Pondoland." Trans. Geol. Soc.
S.A., Vol. XLV, 1942.
WOOLDRIDGE AND KIRKCALDY.-" River Profiles and Denudation-Chronology in Southern
England." Geol. Mag., Jan., 1936.
PLATE J1.
TRlINS. GEOL. SOC. B.A., VOLUME XLVI.
c.
-- -
---
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.
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