Soils and Landforms of the Manjimup Area, Western Australia

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Land resources series Natural resources research

1992

Soils and landforms of the Manjimup area, Western Australia

Hugh Maxwell Churchward

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Recommended Citation Churchward, H M. (1992), Soils and landforms of the Manjimup area, Western Australia. Department of Primary Industries and Regional Development, Western Australia, Perth. Report 10.

This report is brought to you for free and open access by the Natural resources research at Research Library. It has been accepted for inclusion in Land resources series by an authorized administrator of Research Library. For more information, please contact [email protected]. ISSN 1033-1670 AGDEX 524

LAND RESOURCES SERIES No. 10

Western Australia H.M. Churchward

DEPARTMENT OF AGRICULTURE (t1 WESTERN AUSTRALIA SOILS AND LANDFORMS OF THE MANJIMUP AREA Western Australia

By: H.M. Churchward

Editors : L.J. Snell and B Hillman

LAND RESOURCES SERIES No.10 October 1992 DEPARTMENT OF AGRICULTURE Baron-Hay Court South Perth 6151 WESTERN AUSTRALIA ISSN 1033-1670 AGDEX 524

06984-1 The author: H. M. Churchward, Principal Research Scientist; while on secondment to the Department of Agriculture, Western Australia, from the Division of Exploration Geoscience, CSIRO, Perth.

National Library of Australia Cataloguing-in-Publication entry

Churchward, H.M. (Hugh Maxwell) Soils and landforms of the Manjimup area, Western Australia.

Bibliography. ISBN 0 7309 5213 4.

1. Soils - Western Australia - Manjimup Region. 2. Landforms - Western Australia - Manjimup Region. I. Western Australia. Dept. of Agriculture. II. Title (Series: Land Resources Series; No. 10)

631.4099412 © Chief Executive Officer of the Department of Agriculture, Western Australia 1992

LAND RESOURCES SERIES No. 10 2 Page Contents Abstract 5 Introduction 7 Location 7 Climate 8 Geology 8 Physiography 10 Deep weathered mantle 12 Method 13 Soil morphology and classification 14 Mapping units 20 Units of the Darling Plateau (other than those of drainage lines) 20 Units of the Blackwood Plateau (other than those of drainage lines) 31 Units of the Scott Coastal Plain 33 Units associated with drainage lines 35 Acknowledgements 41 References 43 Appendix 1 45

List of figures 1. Location of area mapped—roads, isohyets and towns. 8 2. Broad physiographic features. Location of cross-sections. 10 3. Cross-sections showing the broad topographic trends. 11 4. The relationship of some soil and landform mapping units to general topographic position, shown as schematic cross-sections. 22 5. Topographic sequences for the Bevan and Corbalup mapping units, showing general position of the main soils. 27

List of tables 1. The mapping units 15 2. Correlation of the units between publications 21

3 LAND RESOURCES SERIES No. 10 The soils and landforms of 6000 km2 of the Manjimup area in Western Abstract Australia are presented as two map sheets at a scale of 1:100,000. Forty-eight mapping units were recognized in the area and identified by local names. They related strongly to geology and landforms. The units were categorized into the four broad physiographic features of the area, namely the Darling Plateau, the Blackwood Plateau, the Scott Coastal Plain and the associated drainage elements. Further classification was based on the type of parent material and topography. The soils and vegetation of each unit are described. The capability of each mapping unit for specific land uses was not interpreted.

5 LAND RESOURCES SERIES No. 10 This report is a contribution to The resolution of land use con- the record of the natural resources flicts and good management of an Introduction the of area around Manjimup in area require an adequate inventory south-western Australia. Demand of natural resources. for this information arises from a number of activities including ag- Whilst the nature and distribu- ricultUre, town and regional plan- tion of the soils and the various ning, water conservation, afforesta- landforms are dealt with, their sig- tion and the of regrowth assessment nificance to a range of land uses is potential of sites proposed for re- a separate phase of work generation after clear felling. Fur- thermore, it is essential for environ- The Atlas of natural resources, mental review and management Darling System, Western Australia programmes submitted by propo- (Churchward and McArthur 1980) of mining projects and nents to provides a map, at 1:250,000, of hydrologists part of their as assess- landform-soil units for a large part ment of catchment behaviour, of the western Darling Plateau ex- tending southward to within 12 km The report focuses on the nature of the soils and landforms around ofo Manjimup. Information for much Manjimup which is essential for of the southern part of that map their management, particularly came from an unpublished thesis when they are being variously and by Finkl (1971) on the soils and often intensively used. landforms of the Blackwood River valley. McArthur and Clifton (1975) The natural resources of the mapped soils, at 1:500,000, in the subject Manjimup area are to in- area from Manjimup south to the creased and sometimes conflicting coast Landform-soil units have Much of the yields . pressures. area been mapped along the south coast timber and wood pulp. Also, for- adjacent to the study at and of other indigenous area ests areas 1:100,000 (Churchward et al. 1988). plant communities are a prime re- These maps and the broad scale source for the expanding tourist patterns shown by Sheet Five of the industry and dedicated to some are Atlas of Australian Soils (Northcote various types of parks and nature et al. 1967), useful back- reserves. were a ground for the present study. Significant areas have been cleared for agriculture, particularly Location as a result of the Group Settlement Scheme of the 1920s and 1930s and The area mapped (Figure 1) is meat, wool, fruit and vegetables are about 6000 km2 and lies mainly now produced. Some of these areas between the latitudes 34°00'S and are being replanted to forests. In a 34°30'S and the longitudes 116°30'E few years the soils might be to 115°30'E. A small part extends increasingly used for the growing southward and follows the coast to of vegetables as more of the water latitude 34°44'S. It is encompassed resources of the Swan Coastal Plain by the Manjimup, Donnelly and dedicated urban rather than are to Meerup 1:100,000 sheets and agricultural map use. includes much of the the shires of Manjimup and Nannup. The main There are deposits of mineral Manjimup, Pemberton sands on the Scott Coastal Plain towns are (Baxter 1977). These might become and Nannup. the subject of a land use debate in future, as might the possibility of some stream systems being de- clared as water catchments.

7 LAND RESOURCES SERIES No. 10 Figure 1. Location of area mapped—roads, isohyets and towns.

Climate Geology sediments (McArthur and Clifton 1975; Finkl and Fairbridge 1979), The climate is Mediterranean Much of the area is on the Dar- profiles (Gentilli 1972), winters being cool ling Plateau, the south-western part deep weathered and soils mantle the older rock formations. and moist and summers generally of the Great Plateau (futson 1934), dry and warm. The western sector a major physiographic element of of the area has an average annual south-western Australia. This pla- Archaean gneissic rocks of the rainfall of slightly <1000 mm (Bu- teau is dominated by Archaean Balingup Metamorphic Belt extend reau of Meteorology 1965) but rain- rocks of the Yilgarn Block that is a eastward from the Darling Fault. fall rises just east of the Darling portion of the Western Shield of However, by about 15 km beyond Scarp, possibly as a consequence of Australia (Trendall 1975). It is de- Manjimup, granitic rocks are more an orographic effect. On the pla- fined on the west by the scarp of important (Wilde and Walker 1984). teau, Pemberton has 1275 mm and the Darling Fault. Westward be- Both terrains are intruded by Manjimup, 1000 mm. Rainfall de- yond the scarp, the lower dolerite dykes which have a gen- creases rapidly north of Manjimup Blackwood Plateau is on Mesozoic eral east-west trend, but near the (e.g. 850 mm at Bridgetown), and sedimentary and igneous rocks of Darling Fault north-easterly to to the east (e.g. 800 mm at the prop- the Perth Basin. An array of north-westerly orientations are erty of Deeside). unconsolidated, largely Cainozoic more prominent. Quartzite bands,

LAND RESOURCES SERIES No. 10 8 usually with a general east-west Northcliffe road 2.5 km south of been locally derived and need not trend, are scattered throughout the Pemberton (ref: MG088863). Here necessarily indicate a regionally area, is a thick bed of coarse sand and integrated river system. Some ar- grit with an occasional thin bed of eas of these sandstones have been Mesozoic sandstones, mainly of quartzose cobbles. Some of the incised and the remnants cap local the Leederville Foirnation, affect the sands have crude cross bedding as crests, sometimes associated with a soil pattern in areas of the well as associated, slightly inclined, lateritic duricrust. They occur fre- Blackwood Plateau. Bunbury Basalt thin laminae of silt, fine sand and quently east and west of Quininup, (McWhae et al. 1958), stratigraph- clay. At most other sites, there is as well as north-east of Strachan ically below the Leederville Forma- commonly no clear stratification in mill site adjacent to Muirs High- tion, is within ancient valleys cut these materials and generally loose way, and extend eastwards beyond the boundary ref: in the Yarragadee Formation. It coarse sand and grit provide a map (e.g. at MG542924). outcrops along some of the major sparse matrix to high amounts of valleys and as cliff headlands on cobbles (to 15 diameter). These cm Finkl and Fairbridge (1979) the south coast at Black Point. The beds be at least 2 thick and can m show, in generalized the occasional presence of Bunbury often overlie gritty clay saprolite a manner, a Quagering beds having wide- Basalt on the Darling Scarp (Finkl derived from gneissic rocks. Several as spread while the and Fairbridge 1979) indicates that large of these gravelly depos- occurrence, on areas Pemberton-Irwin Inlet geological uplift of the plateau was probably its, some 17 km west of Pemberton, map sheet (Wilde and Walker 1984) more recent than Cretaceous. have an elevation of 100 to 130 m the unit Tg was proposed to repre- AHD while an isolated pocket, sent some of the unconsolidated, Some of the unconsolidated 6 km south-west of Yornup town- generally quartzose sediments of sediments on the Darling Plateau ship (ref: MH177292), is 280 at m this Observations during the are comparable with Kirup Con- AHD, well above the floor of the area. present work suggest that many glomerate (Finkl 1971). One exam- Blackwood River valley at 120 m. mapped Tg to ple of this material, on the areas as appear comprise colluvial sands forming the Dwalganup Road, 2.5 km north of Another of quartzose de- type lower slope member of Dwalganup Spring (ref: posit comprises sand and grit. It is toposequences common to much of MH472374), occupies a local crest dominated by grains (to coarse the western sector of the Darling the Darling Plateau at 280 3 diameter) that often well on m mm are Plateau (Churchward and Batini Australian Height Datum (AHD), rounded and have frosted surface. a 1975; Bettenay et al. 1980). Further- well above the adjacent dissection Small of this type of sand areas are in the study there are of the Blackwood River. Here adjacent the more, area at Manjimup, to cem- relatively few of Tg cobbles (25 to 50 occurrences quartzose mm etery, at 280 m AHD (ref: confirmed being the Quagering diameter) in sandy silcrete- as are set a MH210096); at the junction of beds. Although several authors like matrix. At another site of west Fernhill and Perup roads (ref: (Finkl 1971; Taylor 1971), have Manjimup (ref: LH922082), re- coarse MH287124), where they occupy a ported that Kirup Conglomerate cobbles exposed in minor are a divide at 250 m AHD, about 8 km continues eastward beyond the excavation below the floor of west of Manjimup; and at Hartlea a study area, just north of the gravel pit at the junction of Quartz (ref: MH547265), just beyond the Blackwood River valley (Finkl 1971; and Coronation roads. These cob- north-east corner of the area Taylor 1971), it could not be traced bles friable clay are set in a gritty mapped. There were traces of this further east from the Dwalganup and have a diameter of up to 30 cm. round grit and coarse sand fraction site. This material, which is beneath 2 in surface horizons of soils from to 3 m of Quagering gravels (see widely distributed sites. The rela- A large body of Quaternary below), comparable is with that tively limited size range, their aeolian sands forms a complex sys- seen at the type locality for Kirup frosted surface and the general lack tern of dunes along the seaward Conglomerate (Finld and Fairbridge of rounded pebbles as companion side of the Scott Coastal Plain. The 1979), a rail cutting about 5 km material, suggests that these quartz older parts of this system are domi- north of Mullalyup (ref: LH996667). grains may have been transported nated by the Tamala Limestone (and worn) by wind rather than by Formation, a low-grade coastal Very sandy materials, generally streams. aeolianite of Pleistocene age with high amounts of smaller cob- (Playford et al. 1976) and much of bles, have been included in the Poorly stratified ferruginous this is overlain by unconsolidated Quagering beds by Finkl and sandstones have been observed on calcareous sands that are similar to Fairbridge (1979). The type locality the Darling Plateau, especially in the Quindalup sands of the west of these materials (as proposed by association with some broad, coast, considered to be of Holocene Finkl and Fairbridge 1979) is a pit swampy tracts when quartzite is age by McArthur and Bettenay on the south-west side of the nearby. The sands appear to have (1960).

LAND RESOURCES SERIES No. 10 Rive 116°30E 115°30E 34°S 34°S

CO River <09 Blackwood A Cross - section I Plateau Darling 0 0.) Plateau Scott I Coastal \ '0 River Plain Lake coastal Jasper dunes Black Point

34°30'S 34°30S (D 115°30'E coastal 116°30E dunes \ •

Southern

coastal dunes Ocean

10 0 10 20 30km 1.--1 II II

Point D'Entrecasteaux

Figure 2. Broad physiographic features. Location of cross-sections.

Physiography that where the plateau surface is network is sometimes sharply trun- relatively undissected between cated the Darling Scarp and Broad physiographic features of at at Yornup and Manjimup, it points where it joins the deep val- this in Figure 2 while corn- area are seen prises complex of shallow drain- leys of major trunk such cross-sections (based 20 a streams, on m con- floors and broad flat interfluves the Blackwood River. Finkl and tour intervals), presented in Figure age as with relief of less than 20 On this Fairbridge (1979) proposed that this 3, illustrate the broad topographic m. little-dissected part of the plateau phenomenon indicates that the trends. some local relief is provided by low drainage pre-dated the plateau The surface of the plateau, with hills rising 20 to 60 m above the uplift and that perhaps the uplift an elevational range of from 260 to broad drainage floors and the took place in several stages. 330 m AHD, declines southward to poorly drained plains. Drainage much less than 100 m AHD. This from these swampy tracts concen- At the general latitude of is in keeping with the regional trates along a system of shallow Manjimup, most of the valleys trend, across what Cope (1975) re- valleys referred to by Finkl and become progressively more incised f erred to as the Ravensthorpe Fairbridge (1979) as the Darling downstream. However, in the case Ramp. In more detail it can be seen Drainage System. This co-ordinated of the south-draining rivers,

LAND RESOURCES SERIES No. 10 10 Cross-section I: A - E, located at approximately 3 4°10'S latitude.

Brook metres Blackwood ilyeannup Plateau West end 100- A of section 0 River Brook 300 Darling Donnelly Plateau Blackwood rice 200 Plateau

100

metres

300

200

01> E a '1;) metres i Darling Plateau EE 300 S a. East end of section ).- - .....

200-

Cross-section II: G - J, from the coast, in a NNE direction metres

South end 100 of section

Sea 0 Level

metres 3 g 300 - g (r) >,

200 -

100

metres

400 -

North end 300 - of section

Figure 3. Cross-sections showing the broad topographic trends.

11 LAND RESOURCES SERIES No. 10 although the valley sides steepen limits of the plain while westwards of the scarp which feature smooth downstream the valleys do not drainage is towards the Scott River. gentle valley slopes mantled by become much deeper since the Low linear dunes <2 m high, with lateritic gravels, sands and plateau becomes lower in that a general west-north-west orienta- duricrust, and by kaolinitic direction. In the eastern sector, tion, are scattered over the surface saprolite. This suggests that deep inclination of the valley sides for of the unit. weathering has been considerable such rivers as the middle course of after the final uplift of the Darling The coastal dunes form system the Warren and much of the Perup, a Plateau and attests to the antiquity rising 100 AHD (147 is variable because local, erosionally to over m m of this feature. at Dickson Trig). Surface sands here active tracts, feature. more are a largely of parabolic These often form amphitheatres are a system dunes that have east-south-east Deep weathered mantle along the valleys and in these, an and an east-north-east orientation. slopes are roughened by frequent In keeping with much of south- This system is comparable with the country rock outcrop; sometimes western Australia (Stephens 1946; dunes of the terminating laterite-cappedMulcahysystemyoungwester 1973), the deep, weathered as the Quindalup. However, the breakaways. coast, mantle comprises deep clay, much sands of the south a coast system of which is clearly saprolitic be- contain less calcium carbonate, Although the Blackwood Pla- so it still has the fabric of the have been referred the Meerup cause teau is generally lower than the to as parent rock. The saprolite is fre- and Clifton Darling Plateau, it has comparable unit (McArthur 1975). quently dominated by pale colours physiographic features. At the lati- The low carbonate content might in (e.g. pale yellow, grey and pale tude of 34°00'S the skyline of the part reflect the effective leach- more yellowish white are common) and Blackwood Plateau is 120 140 ing by rain, but dilution by rework- to m is often referred to as the pallid ing of leached sands from soils of AHD, declining southward to about In the few metres, rock the older dune (i.e. Tamala zone. upper 50 m as it blends with the Scott system fabric is often less and Limestone coastal aeolianite) common Coastal Plain (Playford et al. 1976) or mottling is evident. have been significant. coarse more and there is no scarp. Much of the may more Such material is often referred to The parabolic dunes extend from relief variation is associated with the mottled and it the the broadly ridged as zone merges interfluves between broad swampy coast over upwards into the laterite horizon of the Tamala Limestone and tracts, which often form the head- mass with higher amounts of iron and the inland, waters of the valleys draining the onto swampy terrain aluminium sesquioxides, and is fre- The older materials often lour- Blackwood Plateau. Elements of the are quently indurated. It sometimes has ied by the sands but their Darling Drainage System on the younger spheroidal segregations (i.e. Blackwood Plateau are also trun- core of aeolianite is sporadically pisoliths and nodules) and exposed unstable, coarse cated by the Blackwood River val- on steep, sea- vermiform voids. This horizon is ley. The antiquity of this valley is ward-facing slopes and escarp- often called the lateritic duricrust. scattered, also suggested by paleo-drainage ments, as steeply flanked Weathering of the duricrust yields features which are adjacent to the and sometimes cone-shaped ridges sands and lateritic gravels. Whilst and occasional pockets of calcrete present course. Notable in this re- as much of the lateritic duricrust in cap-rock having specific spect are traces of perched mean- no topog- this to have developed raphy. The leached surfaces of these area appears ders. Furthermore, the skyline of in situ, portions of it comprise older dunes exposed some the plateau declines locally towards are sometimes lateritic gravels that have been through the discontinuous the valley, a gradual trend that is younger transported short distance sand mantle. a sharply truncated by the present downslope and recemented. valley sides. The relief of the Darling Scarp at Erosion of the deep mantle of A well developed pair of terraces Nannup is about 160 This de- m. weathering effects its partial or the floor of the Blackwood clines southward, so that adjacent occupy complete removal, particularly on valley. Another to the southern limit of the River pair occur in steeper slopes. Stumps of it often Blackwood Plateau, and the floor of the Barlee Brook. it is 100 m provide the subsoil of duplex eventually, 10 km beyond Fly profiles whilst debris from erosion The Scott Coastal Plain (Playford Brook, it has no clear expression. forms a colluvial mantle that is a et al. 1976) is an extensive swampy The decline is accompanied by a major contributor to the suite of tract inland of system of coastal change the of a progressive in nature soils. Many of the A horizons dunes. On this the water table is at are the Darling Scarp. Much of the of this transported material. or close to the surface for most of scarp north of the mapped area the year and there are a number of presents rather steep irregular Lateritic duricrusts, and the as- ephemeral swamps and lakes, such slopes with much rock exposed. In sociated very gravelly sands, are as Jasper and Quitjup. Barlee Brook contrast, south of Nannup (just more common on the well drained and the Donnelly River occupy beyond the northern limit of the broad convexities of divides and shallow trenches along the eastern map), there are increasing sections low hills. Where the crests are

LAND RESOURCES SERIES No. 10 12 broad and poorly drained, Plateau which range from strong duricrust outcrop is limited to the brown, red-brown, strong yellow- convex flanks of the crests. This ish brown and dusky red. The ex- appears to have a significant bear- ception is the duricrust which ap- ing on the regional extent of lateritic pears to be over Bunbury Basalt duricrust. The overall extent of and which has a colour closer to lateritic duricrust on the Darling duricrust of the Darling Plateau, On Plateau in the Manjimup area is not the Blackwood Plateau, lateritic as great as on the Darling Plateau duricrust occurs more frequently on east of the Perth area. This appears upper slope convexities. Tabular to be partly related to the more fre- divides on this plateau are common quent occurrence of sandy, often however, and are more often occu- swampy tracts (e.g. the Corbalup pied by deep sands than by lateritic and Yomup units of the map in this duricrusts. report) forming tabular divides on the southern parts of the Darling method Plateau. On a regional scale this The mapping units relate trend is perceptible on the Darling Plateau south of the Preston River strongly to geology and landforms. near Donnybrook. North of this The soil pattern in south-west- by local interfluves river, contrast, em Australia is related closely to of the Darling Plateau are more the degree of stripping of the deep often broadly convex and exten- weathered mantle. On the gently sively capped by lateritic duricrust. undulating plateau surface, sedi- broad slope There also notable variations ment from up convexi- are delivered adjacent slopes in the distribution of lateritic ties is to and, with the lack of active streams, duricrust within the study area. In accumulates close to the By a narrow zone immediately east of source. the Darling Scarp, south of contrast, there is more stripping in sediment Manjimup, the interfluves have the deeper valleys. Here slope and along much lateritic duricrust. However is moved down the the active easily, the duricrust decreases to the east streams more ex- of this Immediately north of posing fresh rock and deeper parts zone. of the weathered profile. Geology Manjimup for some distance are determines largely the amount of extensive swampy divides, which sand, clay, iron in the account for the general lack of or quartz may weathered mantle. These affect the lateritic duricrust on this part of the susceptibility of the mantle to plateau. Here the duricrust is com- ero- the nature of the colluvium, mon only on the occasional sum- sion, the type of weathered material mits rising above the swampy exposed in the of stripping and plains. Laterite is also not common course the of soils. on interfluves south and south-west array of Manjimup where the ridge crests The area's geology, landform are occupied by the Crowea unit. and soils were examined while tra- The colluvium that mantles much versing roads and were delineated of this unit often contains fragments during stereoscopic examination of of basement rock, reflecting per- 1:40,000 black and white aerial pho- haps greater stripping of the weath- to grap hs (WA1303 Pemberton; ered mantle. 23.12.70). A base map at 1:50,000 first compiled and reduced The duricrusts of the was to the final scale of 1:100,000. Blackwood Plateau are generally more sandy than most of those on the Darling Plateau, suggesting the rather more quartzose nature of the underlying sedimentary rocks. They often have reddish brown, brown and light brownish mottles and colours that are not as strong as the duricrusts on the Darling

13 LAND RESOURCES SERIES No. 10 The soils have been classified They occur in several landscapes Soil morphology and according to A Factual Key for the where drainage is not restricted, in Recognition of Australian Soils particular on some of the linear classification (Northcote 1979). In this system, dunes in the Blackwater unit. They soils are first grouped according to also occur in the Quartzite unit on field texture profile. This may be the gentle lower slopes that flank uniform throughout (U, undifferen- quartzite ridges. tiated), gradually increase with Sandy soils with weak horizon depth (G, gradational), have or a development (Uc5.11, Uc5.12, Ks- sharp texture break (D, duplex). Uc5.11) have slight changes in tex- The uniform soils divided into are ture, colour and consistence. No A2 textured sands (Uc), medium coarse horizon is evident and there (Um, barns), fine may textures textures be variable incidence of lateritic (Uf, clays) fine for soils a or textures gravels. Colours generally yel- that crack seasonally (Ug, cracking are low-brown to reddish brown. These clays), soils occur on the long gentle lower There are two classes of grada- slopes of some hills and on upland tional profiles: with calcium carbon- concavities, especially where there ate (Gc), which does not occur in are ferruginous gravels upslope. the study area; and without carbon- They are elements of the soil man- ate (Gn). tle in the Mattaband, Corbalup, Bevan, Kingia, Carbunup, Bidella Duplex soils have abrupt texture and the Layman units. changes between the A (surface horizon) and the B horizon (sub- Po dzols soil). They are divided according to the colour of the clay B horizon into Many coarse-textured profiles, red (Dr) or yellow (Dy) classes, having marked colour differentia- tion with depth, can be classed as Further subdivision in all classes podzols. These soils have a is based pH, structure, consist- on bleached A2 horizon and a well- ence and fabric to determine the defined B horizon coloured by Principal Profile this ac- Form (PPF). In cumulations of various admixtures the PPF well the Great paper as as of iron and humus. They occur in Soil Group (Stace et al. 1968) will sandy tracts; some are on well- be used to classify the soil. drained sites such as sand dunes; The mapping units referred to in others in swampy terrain. Podzols the following soil group descrip- (Uc2.21, Uc2.22) tend to be associ- tions are listed in Table 1 on pages ated with better drained sites while 15-17, and are described on pages humus podzols (Uc2.20, Uc2.33) are 20-40. common on poorly drained sandy tracts. Uniform, coarse textured soils In the podzols, the B horizons The uniform, textured coarse be friable yellow-brown light (Uc) soils of the study di- can to area are brown sand but often have vided colour, incidence of cal- more on streaks of various shades of dark cium carbonate and induration in brown and black. Some of these the B horizon. Calcareous sands soils have strongly convoluted (Uc1.11) with colour differentia- a no interface between the A and B ho- tion down the profile other than rizons, feature that is often high- that associated with organic matter a lighted by dark brown (to accumulation in the surface, a zone occupy 40 thick) developed the the phases of coastal dunes cm at top younger of the B horizon. The B horizon is within the Meerup mapping unit. sometimes weakly cemented, form- Undifferentiated siliceous sands ing nodules or a discontinuous pan. (Uc1.21) have no horizon develop- These soils are similar to iron ment other than organic matter podzols and are common in dunes accumulation in the surface. Some on the swampy coastal plains (i.e. of the profiles possibly have a B in the Blackwater unit). These pro- horizon beyond examination depth. files are an important part of some

LAND RESOURCES SERIES No. 10 14 CRd)

CRy,

(CRb, H 0 BE CR CL CP HK QT QP C.)

Milyeannup Mattaband Kapalarup Quagering , Quartzite Jangardup DicksonWishart Toponup Cormint Angove Telerah Yornup Forrard Kingia Gale Collis g''' Scott 0 e.3 -20 cd 0 0 PO> 0 UL) O L)t4

cobbles rare divides; very loose quartziteoutcrops laterite outcrop undulating divides; common present dividesdivides divides; some Conglomerate quartzite Quagering relief smooth irregular valley gently dunes often low duricrust with local local local sandstone floors rare broad - - divides of undulating slopes to undulatingsome beds undulating undulating - fringes slopes high convex convex Kirup rises; plain swampy lateritic - low, Quagering high flat Ferruginous Weathered m flat Undulating low Stripped Swampy Swamps Silicified on Bevelled 40 m Broadly Broadly Slightly Almost Almost N Slightly Slightly Slightly Some Often Broad to 20 some 0 20 < a of general elements

above plateau emergent surface surface tracts tracts tract t Footslopes ridges Undulating a.)0 Swampy hills Swampy Swampy Scarps plateau Plateau Plateau Scarps tE Hills Low Low g P. 1

fringeplateau the

of western g Units the 1 A 0 cc! • 8 ga, g of P.,

on - rocks '00 developed Basalt t4 on :g) '1E/It 0 developed Mesozoicsediments crystalline 0, Bunbury units 7-A 7:t), o 0 1 , A TU — o Units Units t . 0• >d.) 0 0 ••o0 0 :t mapping It 0 E A 7000-'0 0 .a)

0 ,0 The t rl8 1. -0 Table A -g A Pq A

15 LAND RESOURCES SERIES No. 10 Mu)

Mc,

Mp,

Mf,

BW (Ms, AD LL, E- 14 al 4 b 5

Blackwater C 0 0 3 0 0. .E, >, 0 ,.- a, o Meerup 49 aC .. .-A 0 E .a Cleave - =0 <1.)a -t

drainage

.4 s° co .4'1 0 so ,, . _.• defined deep;slopes plain slopes -,-,„ deep; deep; ca, E o' 7,' E . , slopes slopes . ,c)i-cdo oL CoEL E. ogoa deep: m CV 0) N p CI p 0 p) ©o 10° Swampy •—. _ 40 Slightly . o ' N ' ‘• 0 71- ‘" — ' ' 0 V , 00 8° - 2 0 ` — ,S) ' 0— ' 0 0 ' — 0 0 ' — .. E 00 m m , c o ,' -,-, '-' o -' o - o 0 Co CC © m to <20 <5° to to 20 <30 ,.. . .., 0 . - o. .,._. .o .,..., *, „-, -, -- c',1- - "1 ,2. 0 0 0 0 0 0 0 20 3° 20 30 ,-.5 - v - ,c -~ -71- -4 N v", ,i- v N v cn < some

types, Limestone

parabolic tracts) tracts valleys Tamala c•-•' -a '2 a0 Swampy -",-^ - (swampy ,-d0 -a") Mainly 0 Minor over C ;di a 3 -a (.>

systems

dune sediments N of bil 0 7'i coastal 0 cO .- Mixed Sands v) 0 ..••• O) CE, 4 ig -45.. - 0 0 Q 01-1 Continued -,

v) 0 the Coastal 0 • of Plain OD ai 1. Units Scott • 0 Table '-)

LAND RESOURCES SERIES No. 10 16 0. 0 td) Layman d Bidella .- 8 at A .. cti

deep;slopes deep;slopes deep; deep deep m m deep;slopes slopes 12° 12° 60 40 m m m to to to to 20m <3° <20 <3° <20 <10 40 8° 20 5°

valleys valleys valleys

Major Minor Major

incisionsswampy Coastal plain 0 '0 E the 0 o 3 a" on . N 0 coastal 4 —N40 Units Scott Plain; a il into .5 . 4 .,0a) . Continued 0 a) —,3 .5 .5 2 eo Table!. V o •,-,5 .cl .,

17 LAND RESOURCES SERIES No. 10 06984-3 A variety of land uses occur within the study area.

of the older elements of the Meerup the Blackwater, Quagering, Yornup, Cormint, Biddela, Coate dune system, and minor, though Angove, Yornup and Cormint and Blackwater units, and in the significant parts of the soil mantle units. swampy interdune flats of the in the Blackwater, Cormint, Kingia, Meerup unit. They can occupy Peaty podzols (Uc3.33) Coate and Cleave units where deep contain much of the swampy floor of the moderate large (usually sands occur in well drained situa- to amounts Yanmah unit. Other loamy soils are <20%) tions. of organic matter in the on many of the lower terraces. They surface horizons. The A2 horizon range from brown friable sandy is usually with sporadic Sandy soils with a definite but grey barns to sandy clay barns with a not bleached A2 horizon and a col- bleaching, and the B horizon con- pH between 6 and 7 (Um5.52). Such of black hardpan. oured B (Uc4.21) can be referred to sists a organic soils are in the Bridgetown, as podzolized sands. These are in These profiles are mainly in the Balingup, Donnelly, Warren, Blackwater, Angove and Quagering the Meerup system (Ms, Mp and Lefroy, Wheatley, Wilg ar up, sometimes Mc). The presence of units. Yerraminnup and the Strachan these soils can sometimes relate to units. of the leached surface of exposure, Loams the older dune system, (on Tamala Limestone) showing through the Loamy soils (Um) are not corn- Uniform, fine textured soils discontinuous mantle of the There small in mon. are areas Uniform, fine textured soils younger Quindalup sands. Mor- poorly drained tracts along valley are not common. Cracking clays phologically, the soils are similar to floors and plains, particu- swampy (Ug5.13) the floors the Karakatta series (McArthur and larly where iron-rich groundwaters are on swampy of the Kapalarup, Catterick and Bettenay 1960) as part of the discharge. Reddish yellow barns Carbunup units, with some non- Spearwood dune system on the (Um5.21) usually characterized are cracking clays (Uf6.42) also in the Swan Coastal Plain. by very bright reddish yellow- or Kapalarup unit. ish colours and the soils are often Humus podzols (Uc2.20, Uc2.33) referred to as orange earths. Tex- have B horizons that are dark from sandy barns tures range to Earths brown to black; the boundary be- silty clay barns and the profiles, tween the bleached A2 and B hori- seldom > 40 cm deep, may overlie Soils with gradational increases zons is generally even. Some B bog-iron pans which, in turn, over- in clay with depth (Gn) are referred horizons are friable (Uc2.20) but lie a pale grey heavy clay, to as earths by Northcote et at. more often they form a hardpan, (1975). They are mainly on the sometimes referred to as 'coffee These reddish yellow barns oc- flanks of prominent hills and on the rock'. These soils occupy parts of cur as scattered pockets in the lower slopes of some major valleys

LAND RESOURCES SERIES No. 10 18 in the western part of the area. The A horizons but is generally concen- red earths (Gn2.12, Gn2.14, Gn2.15, trated at the interface of the A and Gn4.15) have a brown or reddish B horizons. Such soils make up brown sandy loam surface, 30 to major portions of the Bevan, 60 cm thick, showing much evi- Crowea, Mattaband and Collis dence of biological activity. The units. In this group, where the hue surface is very friable and may of the B horizon is 10YR*, the map contain up to 50% gravel. Below unit symbol is followed by the sub- this the texture gradually becomes script 'y'. When the hue of the B finer, sometimes to medium clay, horizon is 7.5YR the subscript 'b' is and this material may be used. structureless or weakly structured while the colour changes to red or Duplex profiles with very sandy brownish red. Deeper layers are surface horizons (Dy5.81, Dy5.82, generally mottled and fragments of Dy5.83, Dy5.84, Dy5.85) are the weathered gneiss can be present main soils of the Angove, Toponup, below a depth of about 150 cm. Red Kingia and Bidella units. Minor earths, often referred to locally as areas occur in the Bevan, 'karri barns', make up significant Mattaband, Collis and Crowea parts of the Crowea, Mattaband, units. The profiles are characterized Bridgetown, Balingup, Donnelly, by an A horizon which is bleached, Warren, Lefroy and Pemberton and a yellow mottled clay B hori- units. zon. Some ferruginous gravel can be present at the A /B interface. Yellow earths (Gn2.45, Gn2.61, Sometimes there is dark brown Gn2.64) differ from red earths in staining of the soil material at the having slightly shallower (20 to interface suggesting the incipient 40 cm) surface horizons, a firmer development of a 'podzol B' hori- consistency throughout and yellow zon. or brownish yellow subsoils. Yel- low earths are often closely associ- *All colour notations are derived from ated with yellow duplex (Dy) soils, 'Munsell Soil Color Charts' Munsell (1954). in granitic terrain within the , Crowea, Mattaband, Bridgetown, Balingup, Donnelly, Warren and Lefroy units.

Duplex soils

Duplex soils have a sharp texture change and comprise two classes. One class in the study area, the yellow duplex soils, has acidic to neutral profiles and includes various podzols. Others are alka- line at depth, having columnar or prismatic clay subsoils. These are the solodized solonetz and solodic soils which collectively can be referred to as solonetzic soils.

The more common profiles with podzolic character (Dy2.61, Dy2.62, Dy3.61, Dy3.62) have a grey-brown loamy sand to sandy loam surface, on an A2 horizon at 20 to 40 cm and a variously mottled yellow, yellow-brown, brown or yellow- grey clay subsoil. Ferruginous gravel may occur throughout the

19 LAND RESOURCES SERIES No. 10 In all, 48 units are recognized. The mapping units are listed alpha- They grouped according betically. The four Mapping units are to main groupings parent materials, which include are: crystalline igneous and coarse . Units of the Darling Plateau metamorphic rocks, quartzites, (other than those of drainage consolidated sediments (mainly lines) Mesozoic sandstones), unconsol- Units of the Blackwood Plateau idated sediments and • quartzose (other than those of drainage those units associated with aeolian lines) sands and sediments of mixed Units of the Scott Coastal Plain origin on a wash plain. In effect, • this groups units into those • Units associated with drainage associated with the Darling Plateau lines. (including the unconsolidated sediments), the Blackwood Plateau Units of the Darling Plateau and the Scott Coastal Plain which (other than those of drainage are major elements of the area's lines) physiography. Units of the Darling Plateau fall into two categories based Division within the broad group- on parent materials. The units either ings is largely based on topogra- may have developed mainly crystal- phy which means the units are an on line rocks the association of soils, rather than be- igneous — granites and gneisses quartzite and/ ing a single soil type. — or on or unconsolidated quartzose Both major and minor valleys sediments. have been recognized. Major valleys contain a stream channel and Units developed mainly in crys- are commonly, but not always, talline igneous rocks — granites deeper and wider than most minor and gneisses valleys. The minor valleys usually The granites and gneisses of the have swampy floors and are often Darling Plateau contribute to two deep. Classification the not as of broad unit types: major and minor valleys is mainly units of the western fringe of the based the geological setting • on plateau, and through which they pass, their re- of the plateau surface. lief, the configuration of their cross- • units section and the incidence of ter- (1) Units of the fringe races. western of the plateau The units, identified by lo- map The plateau fringe can be further cal (see Table 1), de- names are subdivided into stripped or weath- scribed in of physiography, terms ered slopes of the scarp; or the geology and soil mantle. Some fea- footslopes. tures of the associated native vegetation included. Table 2 are on Scarp page 21 is a proposed correlation between these units and those used Stripped slopes by previous workers in this region, Unit: Dickson DS while Figure 4 on page 22 shows the relationship of the major units This unit comprises irregular to topographic position, in sche- slopes with gradients ranging from matic cross-sections. 12° to 200; minor, steeply graded, first order streams are included. The salient features of the map- The crest of this unit ranges in el- ping units are included in the leg- evation from 300 m AHD, immedi- ends presented with the two map ately south of Nannup, to about sheets enclosed with this report. 100 m further south. It represents

LAND RESOURCES SERIES No. 10 20 Table 2. Correlation of the units between publications the eroded portion of the Darling Scarp. Fresh rock frequently crops McArthur and Clifton Churchward and McArthur Churchward et al. This publication while shallow colluvial mantles, (1975) (1980) (1988) out some with substrates of deeply Angove Part of Quagering Angove kaolinized gneissic (and sometimes Balingup + Balingup granitic) rock, are extensive. This is Barlee the dominant of the Darling Bevan Part of Balbarup Dwellingup Bevan nature Part of Nyanup Hester Scarp southward to about Stewart Bidella Part of Mungardup Road, beyond which the weathered Blackwater Blackwater Blackwater scarp unit Wishart is more exten- Blackwood Darradup sive. Bridgetown+ _ Bridgetown , Carbunup Yarragil ' The soil pattern is complex and Cattaminup Part of Bevan includes yellow duplex, red duplex, Part of Camballup Part of Caldyanup gradational red and gradational Catterick Catterick yellow profiles, all of which have Cleave Part of Blackwater Part of Blackwater an acidic pH. Coate Part of Mungardup Collis Collis The dominant plant community Corbalup Part of Hester Part of Bevan is open forest to tall woodland of Cormint Eucalyptus calophylla (marri). The Crowea Crowea includes Dickson Darling Scarp shrub layer Xanthorrhoea Donnelly Helena V1 preissii (blackboy), Macrozamia riedlei Forrard (zamia palm), Acacia pulchella (west- Gale Kingia ern prickly moses), A. myrtifolia, Hawk Part of Cary Bossiaea linophylla, B. ornata, Hovea Part of Jarrahwood Jalbaragup Hardenbergia Jangardup trisperma, cornptoniana Jasper (native wisteria) and Andersonia Kapalarup Morande sprengelioides. Kingia Kingia Layman Part of Darradup Weathered slopes Lefroy Helena Vi Mattaband Mattaband Unit: Wishart WS Meerup Meerup Meerup This unit comprises moderate, Milyeannup smooth slopes (8° 100) and Noombling* to rep- Pemberton resents the less stripped portions of Quagering Quagering Quagering the Darling Scarp. These slopes are Quartzite Part of Quagering mantled by lateritic duricrusts and Quininup gravels, usually underlain by Scott deeply kaolinized gneissic (and Strachan Murray Telerah Part of Kingia sometimes granitic) rocks; little Toponup fresh rock is exposed. The unit oc- Warren Helen Vi curs sporadically along the Darling Wheatley Murray V2 Scarp and is dominant south of V2 Wilgarup Murray Stewart Road where the general Wishart Kingia Yanmah Yarragil Si surface of the Darling Plateau is <150 Yerraminnup Murray m above the Scott Coastal Yornup Wilga Part of Caldyanup Plain. Part of Camballup The soils are gravelly, light + Bridgetown and Balingup valley forms in Finkl (1971). brownish yellow sands with heavy * McArthur et al. (1977). ferruginous gravel (Ks-Uc5.11). Lateritic duricrust can occur at <1.5 m below the soil surface. There are some yellow duplex soils with a very gravelly, pale yellow- brown sand A horizon.

Tall, open forests and tall woodlands of Eucalyptus marginata (jarrah) are common along with some marri. Banksia grandis (bull

21 LAND RESOURCES SERIES No. 10 N Darling Plateau S I 1 1 BT BE CL YR MT YR CO WL CO YR YN YR

W Darling Plateau E DO BE WA BE LF BE YR CO WH CR YR YN CR PM

Blackwood Plateau Darling Scarp 1 1 1 1 1 1DS BK KI JL KI BD TL KI CE GA

SW scou NE C oastal Coastal Darling Plateau Dunes Plain M BW HK WA CR YN A 0 YN CR PM CR LF CR YN BE YR CO WH

DS Dickson GA Gale CR Crowea BE Bevan CL Corbalup YR Yornup HK Hawk ...... Q Quartzite A Angove .K1 Kingia TL Telerah CE Coate M Meerup BT Bridgetown . . . . . DO Donnelly WA Warren LF Lefroy WH Wheatley PM Pemberton YN Yanmah . . . . . BK Blackwood JL Jalbaragup BD Bidella BW Blackwater . . .

Figure 4. The relationship of some soil and landform mapping units to general topographic position, shown as schematic cross-sections.

LAND RESOURCES SERIES No. 10 22 banksia), Persoonia longtfolia (long- may be occasional outcrops of fresh north and east of Manjimup. In leaf persoonia) and Leucopogon rock and some lateritic duricrust. concept it merges with the Bevan verticillatus (tasselwhileand shrub) form a Corbalup units. However, This is not unit but low tree layer Allocasuarina a common Collis usually represents single there scattered hills the Dar- a fraseriana is of the deeper are on summit whereas of Bevan and on some ling Plateau north and of areas sands. Bossiaea linophylla, B. ornata, east Corbalup have complex of broad Manjimup. It with the Collis a Hovea trisperma, Hardenbergia merges summits and shallow vales. and Bevan units. Mattaband comptoniana, Clematis pubescens and usually comprises single summit and Acacia pulchella in the shrub a Churchward et al. (1988) mapped are with the complex layer. so contrasts more four classes of Collis south of relief of the Bevan unit. Pemberton but in the present study Footslopes it possible consistently Yellow duplex soils domi- was not to are delineate these classes. The domi- Unit: Gale GA having clay nan , a onion wi a yellow duplex soils have hue of 10YR. Some B horizons with nant a This unit is a very gently slop- mottled yellow-grey and brown, hues of 7.5YR but it not ing (apparently) depositional apron occur was structureless clay B horizon Possible to consistently delineate to the Wishart unit. It is dominated (Dy3.61, Dy3.62). These profiles uniform areas of such soils in the by lateritic duricrusts, gravels and have light grey-brown to yellow- of Churchward et al. (1988). a yellow sands but there are scattered manner ish brown sandy loam A horizon In this study the dominant incidences of quartzose cobbles. area with pale A2 horizon. Ferrugi- yellow duplex profiles have light a These cobbles have been observed a gravels in the B hori- grey-brown to yellow-brown A nous occur in a pit just south of the Brockman but they usually horizon with pale A2 horizon and zons are not a Highway, 3 km south-west of a dominant feature. Duplex profiles Nannup township, discrete a mottled yellow-brown and pale as a with a clay B horizon and a hue of stratum about 0.5 thick beneath yellowish grey (Dy3.61, Dy3.62), m 7.5YR are rarely present. There are unconsolidated lateritic gravels (ref: structureless clay B horizon and an small areas of yellow-brown sand, acidic pH. Lateritic duricrusts may LH 853365). sometimes gravelly, in local be present and ferruginous gravels very concavities. The Gale unit extends discon- occur in the B horizon. Some Dr tinuously along the foot of the scarp and Gn profiles are present on lo- Open jarrah forests and tall but places separated from in is it calized steeper slopes. woodlands with occasional by incision, such that of occur stream as marri; scattered Banksia grandis, the Carlotta Brook, about km The vegetation is a tall, open 2.5 Persoonia longifolia and Leucopogon south-south-west of Nannup. jarrah forest with some marri locally dominant. A small tree layererticillatusv form a low tree layer. The soils are mainly very gray- (6 to 8 m) of Banksia grandis, The shrub layer includes Bossiaea elly light yellow-brown sands. Persoonia longtfolia and Leucopogon ornata, B. linophylla, Hovea trisperma, verticillatus commonly Xanthorrhoea preissii, Podocar pus Tall forests of jarrah, with is present. some The shrub layer includes Bossiaea drouynianus (native plum), marri, with understorey occur an linophylla, Xanthosia Macrozamia riedlei, Agonis parviceps of Banksia grandis and Persoonia B. ornata, rotundifolia (southern cross), Hovea and Hardenbergia comptoniana. longifolia. The shrub layer is similar trisperma, Kennedia coccinea (coral to that of the Wishart unit. vine), K. prostrata (running post- Undulating plateau elements and broad (2) Units on the plateau surface man), Hardenbergia comptoniana and crests Clematis microphylla (small-leaf The units on the Darling Pla- clematis.Unit:Bevan BE teau's surface subdivided are This is gently undulating tract topographically into distinct hills, Unit: Collis CO a comprising broadly crests gently undulating terrain and convex more This unit, previously mapped by and shallow minor valleys. It has tracts. swampy Churchward et al. (1988), comprises previously been described by Hills low hills, with smooth slopes and Churchward et al. (1988). Slopes in broadly crests, rising this unit generally <5° and the Unit: Mattaband MT convex no are more than about 20 m above the local relief is usually about 20 to This unit, previously mapped by plateau. Although it is developed 30 m. The crests are about 300 m Churchward et al. (1988) to the on deeply weathered granitic rocks, AHD along the northern border of south of the Manjimup area, com- there may be occasional outcrops the map and decrease to about prises the higher hills rising 20 to of fresh rock and some lateritic 100 m in the south-west. 40 above the surrounding pla- duricrust. m Bevan is most extensive to the teau. Areas of the Collis unit are north and east of Manjimup. South- It has developed on deeply widely distributed on the Darling ward, particularly east and west of weathered granitic rocks. There Plateau but it is most common Pemberton, it is often replaced by

23 LAND RESOURCES SERIES No. 10 Loose gravels of the Quagering beds, 6 km south-wes A duplex soil profile typical of the deeper valleys incised Podzolized sand of the older elements of the Meerup of Yornup township. into the Darling Plateau. dune system.

Kirup Conglomerate as a silcrete on a crest of the Darling Plateau near Dwalganup Spring.

The swampy Scott Coastal Plain, showing the low dunes. The Meerup system forms an elevated mass of dunes in the background. red earth profile (kern i loam) of the deeper valleys Deep, gravelly, yellow-brown sands of the Bevan unit. The profile of a podzol on deep sands of the lower slopes ncised into the Darling Plateau. of the Kingia unit.

Elements of the Meerup dune system: the high crests are on Tamala Limestone, the younger dunes form lower ridges.

(deeply incised valley in the Darling Plateau - the ,efroy unit (in the Warren drainage system, south- outh-east of Manjimup). Crowea on the ridge crests. It occu- to yellow sands as the gravels de- Agonis linearifolia, Bossiaea linophylla, pies most local divides immediately crease in amount and size. Podzols B. ornata, Acacia myrtifolia, east of the Darling Scarp. and humus podzols are in the mi- A. pulchella, Macrozamia riedlei, nor valley floors and have dark Hovea trisperma, Hakea amplexicaulis A deep kaolinitic mantle, weath- brown to black B horizons at 50 to (prickly hakea), Hypocalymma ered from granitic and gneissic 150 cm. Here also are areas of or- robus turn (Swan River myrtle), rocks, is extensive and of outcrops ange earths with a bog-iron pan at Stirlingia latifolia (broad-leafed fresh rock are rare. about 45 to 50 cm, as well as yel- stirlingia), Hardenbergia cornptoniana, low duplex soils having strongly Ken nedia prostrata and K. coccinea. Yellow duplex profiles do- . are rm bleached sandy loam A2 horizons nant and have light grey-brown a and gley features in the clay Unit: Crowea CR loamy sand to sandy loam surface, some B horizon. pale A2 horizon and poorly a a The unit comprises broadly structured clay B horizon, variously con- Areas dominated by yellow du- ridge and the flanks of mottled yellow-brown; 10YR hues vex crests plex profiles having a clay B hori- gentle upper slopes and ridges. are dominant (Dy3.61, Dy3.62). zon with a hue of 7.5YR (Dy3.61, When examples of this unit are Lateritic duricrusts and gravels Dy2.62) were recognized during wide enough, the terrain may be field but slightly undulating, about are important features of the Bevan traversing were not as 20 m unit and distinguish it from the clearly expressed on aerial photo- high. West of Manjimup, Crowea graphs in south of the is AHD but elevation Crowea unit. The duricrust occurs as areas at 300 m its study. differences declines southward about on crests and upper slope convexi- Here, in vegeta- to 60 m tion between classes of the Bevan the Dombakup pine planta- ties (see Figure 5), however, as is near (Churchward al. 1988) af- It adjacent often the case, when the ridge crest unit et tion. is most extensive fected the of the aerial photo- Pemberton and extends south of zone is more tabular the duricrust tone to is usually limited to these convexi- graphs. the mapped area. ties. Tall, open jarrah and marri for- The deep kaolinitic mantle de- On these broad crests, duplex est occurs with an upper tree layer veloped from gneissic rock is a profiles are the extensive soil. They at about 30 m along with a small common substrate to a colluvial have very gravelly, pale yellow- tree layer (5 to 8 m) of Banksia surface mantle. Fresh rock outcrops brown to grey-brown A horizons grandis, Leucopogon verticillatus and are rare. and occasional blocks of lateritic Persoonia longifolia. Small pockets of duricrust on the B horizon. Down Melaleuca preissiana and Banksia The dominant soils have yellow the flanking slopes there are yel- littoralis (swamp banksia) mark duplex profiles with some ferrugi- low duplex soils or deep, gravelly, poorly drained floors. The shrub nous and lithic gravels at the inter- yellow-brown sands. These merge layer includes such species as face of the A and B horizons. Lateritic duricrust is rare. The three classes of this unit recognized by Churchward et al. (1988) have been delineated. Differences in the soil between these classes are mainly related to the hue of the B horizon or the texture of the A horizon. CRb—the main soils have brown, gravelly A horizons often 50 to 100 cm thick, and mottled clay B horizons with a dominant hue of 7.5YR (Dy2.61, Dy2.62). Red earths or red duplex soils also occur.

A tall, open forest (40 to 80 m high) of Eucalyptus diversicolor (karri) and marri is dominant, with Banksia grandis, Allocasuarina decussata and

The Pemberton Valley—Pemberton unit.

LAND RESOURCES SERIES No. 10 26 Shallow sandy gravels on Gravelly sands Gravelly yellow laterite duricrust Podzols (coarse gravels) Gravelly sands duplex soils Podzols and (fine gravels) Yellow and orange sands orange earths Bevan earths mapping unit

Gravelly yellow duplex Gravelly sands Yellow duplex soils some on (fine (coarse soils (sandy Podzols and laterite duricrust Podzols and gravels) gravels) A horizon) orange earths orange earths

Corbalup mapping unit

Figure 5. Topographic sequences for the Bevan and Corbalup mapping units showing general position of the main soils.

Persoonia longifolia as a low tree are mainly Hardenbergia zons, is on ridge crests and appears layer. Of significance in the cornptoniana, Kennedia prostrata, to represent the influence of quartz- dense shrub layer are Acacia K. coccinea and Clematis ite veins or vestiges of a once more- pentadenia, Trymalium flor- pubescens. extensive cover of unconsolidated ibundum, Chorilaena quercifolia, sediments. CRd—these in which du- quartzose elliptica are areas Hovea (oval-leaved plex yellow soils having hovea), Bossiaea linophylla and grey Unit: Corbalup CL sand A horizons, dominant. Clematis pubescens. are These A horizons are 20 to 40 cm This very gently undulating ter- CRy—the dominant profiles are du- thick. The A2 horizon is strongly rain usually has broad, almost flat plex yellow soils which have a bleached. The B horizons are crests flanked by long, gentle slopes pale grey-brown loamy sand to mottled pale yellow, brown and (<3°) that merge with broad sandy, sandy loam A horizon that is 20 grey (Dy5.81). At the interface poorly drained concavities. Some to 40 cm thick and sometimes between the A and B horizons, areas have occasional convex ele- bleached slightly. The clay B a dark brown organic horizon ments. Relief is usually <10 m but horizon has a general hue of or a layer of ferruginous gravel as it increases slightly, Corbalup 10YR that is usually mottled is common. tends towards Bevan. On the other yellow, yellow-brown and hand, the poorly drained grey. A marri and jarrah tall, more ex- It is mildly acidic. There are low open amples of it are akin to Yornup. forest (30 to 40 high) is to moderate amounts of ferru- m corn- and there is low layer ginous gravels in the A horizon mon a tree The Corbalup unit occupies sig- (6 m) of Banksia grandis and (Dy3.61, Dy3.62) but boulders of to 10 nificant portions of the plateau on Persoonia longifolia, and shrub deeply weathered granitic rocks this material are rare. a layer containing Acacia myrtifolia, north-west and north-east of and jarrah Tall, open marri Agonis parviceps, Macrozamia Manjimup between the valleys of forests (30 to 40 high) domi- m riedlei, Lepidosperma spp. (sword the Blackwood, the Donnelly and these but karri nate areas some sedges), Kin gia australis (black the Warren Rivers. There few be included in the higher are may gin), Adenanthos obovatus (basket of country rock, how- rainfall Scattered Banksia exposures areas. flower), Xanthorrhoea preissii and and scattered pockets of fer- grandis, Persoonia longifolia and ever, Podocarpus drouynianus. ruginous quartzose sandstone Xylomelum occidentale (forest occur as well as some bog-iron pans. pear) form a small tree layer. A In the mapped, CRb tends area There are scattered blocks of dense shrub layer includes to be the flanks of the ridge tops on lateritic duricrust on low rises. Bossiaea linophylla, Acacia and merges downslope with major myrtifolia, A. pulchella, Hovea valley units such as Donnelly, Yellow duplex soils (Dy5.81) are elliptica, Macrozamia riedlei and Warren and Lefroy. In contrast, extensive, particularly on the broad Xanthorrhoea preissii. Creepers CRd, with its more sandy A hori- convex elements of this unit (see

27 LAND RESOURCES SERIES No. 10 Figure 5). Such profiles have a light (10YR) dominate the B horizon but dunes and hummocks. Red earths grey-brown loamy sand A horizon some have brown hues (7.5YR). are on exposed saprolite, particu- with a pale A2 horizon; the poorly There may be variable amounts of larly when it is derived from Bun- structured clay B horizon is mot- ferruginous gravels in the A hori- bury Basalt. tied yellow and yellow-brown. The and occasional laterite blocks zon Tall forests dominant. pH is acidic. Some lateritic gravels at the interface between the A and open are Karri is important adjacent to the present at the interface of the A B horizons. Orange earths are valley of the Warren River but and B horizons. Down the long (Um5.21), often with bog-iron pans jarrah and marri frequent gentle slopes flanking the broad and humus podzols, dominate the are more south-west of Fly Brook where the convexities, these soils with drainage floors and the ephemeral merge soils sandy. There light brownish yellow sands thence Dark brown to black iron/ are more are swamps. thickets of Banksia littoralis with podzols the floors organic at about some on swampy pans can occur and Melaleuca preissiana, with of the broad concavities. Here also 100 cm. Oxylobium lanceolatum. there be earths can orange Marri-karri forest communities (Um5.21), with bog-iron at a pan dominant, with Banksia grand is Swampy tracts about 40 well yel- are cm, as as some and Persoonia longifolia important low duplex profiles with bleached as Unit: Yornup YR low (4 to 8 m) tree species. The A2 horizons. shrub layer includes Bossiaea This unit forms swampy plains Open forests occur with jarrah linophylla, B. laidlawiana, Acacia and includes some broad, low gra- as the dominant tree species. Some myrtifolia, A. pentadenia, Leucopogon dient drainage floors and occasional marri can be present. A low tree verticillatus, Agonis parviceps and semi-permanent swamps. Scattered, layer (4 to 8 m high) comprises Hovea elliptica. In more swampy low rises are also present. Local Banksia grandis and Persoonia pockets Banksia littoralis and relief is usually not more than 5 m. longifolia with Allocasuarina Melaleuca preissiana occur with The Yornup unit is most extensive fraseriana on pockets of deeper Oxylobium lanceola turn and north, north-east and north-west of sands. The shrub layer includes Lepidosperma ion gitudinale (common Manjimup. It occurs at about 300 m Bossiaea linophylla, B. ornata, Agonis sword sedge). AHD on the Darling Plateau above linearifolia, trisperma, Stirlingia valley of the Blackwood Hovea Unit: Hawk HK the River. latifolia, Acacia myrtifolia and From here it grades south-west to- Astartea fascicularis. Thickets of This is a very gently sloping to wards the main elements of the Melaleuca preissiana and Banksia slightly undulating terrain with Donnelly River drainage system. littoralis mark the swampy some minor swampy drainage more Sandy materials dominate the areas. floors. surface and these overlie clays that low, broad Unit: Cattaminup CF The unit occupies a are mainly kaolinized granitic divide between the dissection of the rocks. The origin of the sands is not This is gently undulating the north and a very Warren River to east, clear but some may be terrain of low relief. Low rises have and elements of the Scott Plain to unconsolidated quartzose broad crests alternating with shal- the south and west around the sediments. low, broadly concave or flat drain- southern limits of the Darling Scarp. age floors. There are a few small The unit ranges from 60 to 110 m Humus podzols (Uc2.33) are the ephemeral swamps. Relief from AHD. dominant soils. These have dark crest to floor is generally <10 m. grey organic sand A horizons with Aeolian sands, as an extensive dark brown to black iron/organic The unit is the Darling Pla- surface mantle, form hummocks, on B horizons at about 50 to 120 cm. teau, occupying a broad divide low dunes and sheets. Quartzose between the Shannon River and the cobbles can be at or near the sur- Yellow duplex profiles are also Tone-Warren drainage system. Gra- face. Saprolite from gneissic rocks common and can be dominant. nitic rocks, deeply kaolinized, are is a frequent substrate to these They generally have sandy, dominant, sediments and there are rare, small bleached A2 horizons and mottled, outcrops of Bunbury Basalt. structureless clay B horizons that The soil the broad pattern on have an acidic pH. Some yellow crests and upper to middle slopes The dominant soils are red- duplex profiles with bleached A2 is a complex array of yellow du- brown to yellowish red loamy horizons and coarse-structured clay plex soils, and of red yellow sands (Uc5.21) with bog-iron, either or B horizons are present. earths. The yellow duplex soils as a pan or as coarse nodules, from have a pale yellow-brown A hori- 40 to 80 cm deep. Quartzose cob- Rarely have calcium carbonate zon with an A2 horizon which can bles may sometimes be embedded nodules been observed deep in be bleached. The clay B horizon, at in the pan. Humus podzols, with these soils (W.M. McArthur, per- about 40 to 50 cm, is structureless friable dark brown iron/organic sonal communication). There can be and usually mottled. Yellow hues pans at 1 to 1.5 m, occupy the low dark brown organic staining at the

LAND RESOURCES SERIES No. 10 28 interface of the A and B horizons. nodosus (knotted club rush), Low hills On the low rises, yellow duplex Leptocarpus scariosus and Juncus pal- Unit: Quininup QP soils are present, often with some lidus (giant rush). Shrubs such as ferruginous gravel, and the A2 Agonis parviceps, Melaleuca acerosa This is a complex of low, horizons be either conspicu- and Beaufortia (sand heath can squarrosa smoothly convex hills, and vales, ously or sporadically bleached. bottlebrush) are usually present. associated with ferruginous sand- duricrust but there of jarrah woodland with Lateritic is rare Some areas stone, sandy lateritic duricrust and scattered bog-iron usually marri, Banksia grandis and Persoonia are pans deep, coarse grey sand. The unit is overlain by shallow, bright reddish longifolia lunettes. occur on not widespread but is most exten- yellow or grey-brown barns. sive and of Quininup Low open woodlands of Banksia east west township. A specific example is Low open woodlands of Banksia littoralis and Melaleuca preissiana oc- adjacent Grays Road (ref: littoralis and Melaleuca cuticularis cur frequently. Tall woodlands of to MG283890). Elements of ferrugi- occur, along with Melaleuca jarrah with Banksia grandis and sandstone low preissiana and Banksia verticillata B. ilicifolia are found on the lunettes nous on or near crests, be relics of previous (river banksia), but there are also where they are associated with a may a large of heath and sedge shrub layer of Leucopogon land surface that has been frag- areas corn- mented by munities. Pockets of jarrah wood- verticillatus, Podocarpus drouynianus, stream incision. Much lands and low forests with Agonis parviceps and Adenanthos of the quartzose sand and grit some which body marri and Banksia grandis obovatus. makes up the of the are sandstones could have been de- present especially on the low rises, rived from quartzite, which occa- A dense heath layer often includes developed Units on quartzite sionally outcrops. Hakea ambigua, H. varia (variable- and/or unconsolidated quartzose leaved hakea), Kingia australis and sediments Crests and upper slopes are Agonis parviceps. In wetter parts mantled by pale brownish yellow Anarthria scabra, Leptocarpus These units of the Darling Pla- gravelly sands with ferruginous low ridges, scariosus, Mesomelaena spp., Gahnia teau are recognized as sandstone and lateritic duricrust at decomposita (a sedge) and Evandra low hills, undulating plateau and shallow depth. Fragments of this aristata tracts. occur. swampy lateritic duricrust are made up of a of dark reddish brown red- Unit: Kapalarup LowKP core to ridges dish black material with some yel- This unit comprises semi-perma- lowish red and pale yellow mottles. Unit: Quartzite QT nent swamps and adjacent elements The outer surface is studded with of the swampy plains. These are This unit comprises ridge crests coarse quartzose sand and grit. The areas of low relief (< 5 m) but some and low hills. It may also occupy deep sands of the flanking slopes sand lunettes may rise to 10 m. The local slopes flanking some of the and the local concavities are domi- Kapalarup unit ranges from 200 to ridges that form some of the nated by humus podzols (Uc2.20) 300 m AHD and is scattered on the Toponup unit, with pale grey A horizons and fri- Darling particularly able dark brown B horizons at 1 to Plateau, north- The unit is dominated by coarse west, north and north-east of sands and grits, and angular 1.51n. Manjimup. quartzite gravels. Occasional pock- This unit is dominated by open ets of cobbles suggest that fluvial The unit is mantled by locally- jarrah forest communities with a p may have contributed to low layer of Banksia grandis and derived lacustrine silts and clays as tree some areas of this unit, dense shrub layer such well as some aeolian sands. A deep a containing mantle of kaolinized granite forms The soils are mainly podzols, species as Agonis parviceps, usually with developed linearifolia, Adenanthos obovatus, a common substrate. poorly iron A. or iron/ organic B horizons at a Macrozamia riedlei, Pultenaea The soil pattern is a complex of depth of 1 to 2 m. reticulata and Podocar pus non-cracking clays (Uf6.42) and drouynianus. Open woodlands of jarrah cracking clays. There are occasional are pockets of yellow duplex soils with dominant along with small trees of Banksia ilicifolia (holly-leaf banksia), Undulating plateau elements a conspicuously bleached A2 hori- Xylomeuml occidentale, Nuytsia flori- zon. Podzols are on the deep sands Unit: Toponup TP bunda (Christmas tree), Allocasuarina of lunettes and humus podzols are fraseriana and dense shrub layer This unit forms broad ridge on the deep sands of swampy a a capped by lateritic duricrust tracts. of Pultenaea reticulata, Adenanthos crest obovatus, Dasypogon bromeliifolius in which there is a scatter of angu- Sedgeland communities are the (pineapple-leaved dasypogon), lar quartzite fragments. Some of the common vegetation and often in- Macrozamia riedlei, Podocar pus laterites are very coarse sandy clude Evandra aristata, Scir pus drouynianus and Agonis parviceps. while there are occasional small

29 LAND RESOURCES SERIES No. 10 pockets of black ferruginous sand- sessilis and Banksia grandis. Several large areas of this unit stone. The unit rises gently from 180 Macrozamia riedlei, Xanthorrhoea are at 120 to 160 m AHD south-west to 240 m AHD. preissii, Boss iaea linophylla and of Pemberton (e.g. near the junc- Leucopogon verticillatus are impor- tion of Benghazi and Fly Brook Areas of this unit occur adjacent tant elements of the shrub layer. Roads, ref: MG966867). An area to Frosty Road, 8 km east of west of Yornup (ref: MH177292) Nyamup township, and few kilo- on a Swampy tracts the Darling Plateau above the val- of township. metres east Quininup ley of the Blackwood Unit: Cormint CT River, is at 280 AHD Another, 13 km south The dominant soils are gravelly, m . pale brown sands. Some of these This is a complex of swampy of Nannup, is immediately east of are deeper than 1 m while others tracts and low rises adjacent to the the Darling Scarp, at 220 m AHD have <30 cm of sand over lateritic Toponup, Quininup and Quartzite (the corner of Wishart and duricrust. There are pockets of light units. It shows coarse quartzose Davidson roads, ref: LH900247). yellow sand and gravelly sand sand, angular quartzite gravel and as The dominant humus well deep, pale sand scattered, small outcrops of quartz- soils are as some grey podzols profiles. ite. A kaohnized granitic substrate but some peaty podzols are The iron/organic B hori- to the soil mantle is common. present. Open jarrah forests and wood- zons sometimes form pans and the lands with some marri are the The Cormint unit is of limited water table is usually at <1 m for dominant communities. Banksia extent; there are several examples much of the year. grandis and Persoonia longifolia are east and west of Quininup town- important low tree species. The ship, generally arrayed close to lati- Low open woodlands of shrub layer usually contains tude 34°27'S. depauperate jarrah, Nuytsia flori- Bossiaea linophylla, Leucopogon bunda and Banksia ilicifolia are The soil mantle comprises verticillatus, Xanthorrhoea preissii so a coin- present. There are extensive heath ' plex pattern of humus, iron and Macrozamia riedlei and Podocarpus communities either as a dense sub- peaty podzols while low rises have drouynianus. stratum to the low tree layer or by yellow duplex soils with pale grey, themselves. This heath includes Unit: Forrard FR sandy A horizons. Agonis parviceps, Pultenaea reticulata, Kingia australis, Beaufortia This unit forms crests and flank- Heath communities are domi- sparsa (gravel bottlebrush), Evandra ing upper slopes capped by Kirup nant but there is a scatter of low Conglomerate. The capping often trees including jarrah, Nuytsia flori- aristata, Lepidosperma gladia turn (coast sword sedge) and comprises a silcrete which encases bunda, Banksia littoralis and Leptospermum firmum. coarse (to 35 cm diameter) Melaleuca cuticularis. A dense shrub cobbles. The layer includes species such quartzose steep ero- as Unit: Angove A sional slopes flanking these crests Agonis parviceps, Pultenaea reticulata are strewn thickly with loose cob- and Lepidosperma longitudinale. This unit, previously described bles. by Churchward Unit: Quagering Q et al. (1988), comprises gentle slopes and A small of this unit is very some area on The Quagering unit has flat broad drainage divides. the plateau surface, above the dis- to It is some- gently sloping, poorly drained, times identified the edges of the section of the Blackwood River, at very on sandy with Quagering where the northern limit of the (ref: terrain, sometimes a unit it appears to map complex of low rises. It often slight erosional modifi- MH472374). oc- represent a curs on broad valley divides and cation of the Quagering unit. Local The soils of the crests are stony, ridge crests some 20 to 60 m above relief is <20 m and it ranges from grey to pale yellow coarse sands. the present stream channels 60 to 250 m AHD. On the flanking slopes are duplex (Churchward et al. 1988). The surface of this unit is domi- yellow profiles with a stony, light The surface is dominated by nated by sands and grits. brown sandy loam A horizon over quartzose deep, unconsolidated quartzose yellow-brown to brownish yel- The presence of cobbles indicates a sediment but there low, poorly structured clay B hori- are some zones that some of the quartzose materi- of quartzite. Frequently this sedi- als of sedimentary origin. Oth- zon. The A2 horizon has sporadic are ment gritty sand bleaching. A stone line in the A comprises coarse ers appear to have been derived of horizon comprises fragments of containing varying amounts from local quartzite. The substrate cobbles and referred diverse origin suggesting colluvial coarse is to as to the sands is often kaolinitic clay, a the Quagering beds. Crude stratifi- nature. the result of weathering of gneissic cation of sands and clays, some- rocks. Open forests to tall woodlands times cross-bedded, may be evi- of jarrah, with some marri, domi- dent. Deeply kaolinized granitic The dominant soils are yellow nate these areas. Low tree species rocks form substrates for these duplex profiles with a light grey- include Persoonia longifolia, Dryandra unconsolidated sediments. brown sand A horizon, having a

LAND RESOURCES SERIES No. 10 30 bleached A2 horizon over a mot- mottled clay B horizon is usually The soil pattern is complex. tied, structureless clay B horizon, structureless, and some ferruginous Lateritic duricrust occurs most fre- The profiles are acidic (Dy5.81). gravels are common in the A2 ho- quently on the broadly convex sum- Dark organic staining is common rizon along with blocks of laterite. mits of low rises. Here also are at the interface of the A and B ho- Humus podzols have developed on gravelly, pale yellow-brown to pale rizons. These soils merge with hu- deep sand and have a dark brown yellowish grey-brown sands, rang- mus podzols developed on deep to black iron/ organic B horizon, ing in thickness from <30 cm to sand. sometimes as a pan, at about 1 m. 100 cm. Some areas of deep, pale Water tables depth of 1 Low woodlands of at a < m are yellow-brown to brownish yellow open in these profiles for about depauperate jarrah and Banksia common sands occur downslope and these months each ilicifolia, Xylomelum occidentale and six year. grade laterally into deep, light grey sands which be classified Nuytsia floribunda are usually On the there pale yel- can as crests are humus podzols. Some of the long, present. A dense heath layer is low-brown gravelly sands with gentle slopes of the crests have dominated by Agonis parviceps, much lateritic duricrust at shal- very a sandy, yellow duplex profiles but Pultenaea reticulata, Kingia australis, low depth. Down the gentle slopes, there significant of soils Adenanthos obovatus, Leucopogon pale yellow sands with ferru- are areas some with gradational profiles. These australis, Leptospermum firmum, and ginous gravels become are more com- yellowish grey-brown sandy Mains Dasypogon bromeliifolius. On the lower slopes, the yel- mon. merging to pale yellowish brown low sands to podzols and Units of the Blackwood Plateau merge sandy clay loams at depth of humus podzols in broad shallow a (other than those of drainage 15 Ferruginous gravels concavities. Where the crests cm. some- lines) are times at 30 to 40 set broad and tabular, lateritic appear cm, in mottled pale brownish yellow Geology divides the units the duricrust is In this a on not common. and light yellow sandy clay. The Blackwood Plateau into those de- situation the crests mantled by are gravels increase with depth, veloped either Mesozoic humus podzols with black iron/ coarse on but then decrease to about 1 sediments crystalline rocks. organic B horizons mottled m or over where the profile is mottled clays having gley features. How- developed light brownish yellow to pale Units on Mesozoic there is of ever, a narrow zone yellow-brown and sandy sediments lateritic duricrust associated with orange clay. All units developed on Mesozoic the convexity flanking the crest. sediments located the pla- Areas of this unit are dominated are on Woodlands most fre- by depauperate, low, wood- teau surface. There two topo- occur open are quently but the wetter parts lands jarrah and graphical categories: undulating are of marri. dominated by heath and sedge Allocasuarina fraseriana and local divides and swampy tracts, communities. The woodlands are Xylomelum occidentale are on some Undulating local divides mainly jarrah, with some marri, of the deeper sands. A dense shrub while a low tree layer contains layer is and this includes Unit: Kingia KI common Banksia grandis, Xylomelum Agonis parviceps, Kingia australis, This unit was mapped by occidentale and Allocasuarina Hypocalymma angustifolium, Churchward and McArthur (1980). fraseriana. The dense shrub layer Adenanthos obovatus, Dasypogon It comprises gently to slightly un- comprises a wide range of species hookeri and Lepidosperma angustatum. dulating ridge crests which form such as Podocar pus drouynianus, A low heath dominates some ar- many of the local drainage divides Agonis parviceps, Kingia australis, eas, particularly those of grada- of the Blackwood Plateau includ- Pultenaea reticulata, Adenanthos tional profiles. Epacrids are com- ing the upper ends of minor val- obovatus, Dasypogon hookeri and mon and include Andersonia leys. At the foot of the Darling Lepidosperma angustatum. sprengelioides and Leucopogon Scarp, crests of these units are aboutcapitellatus. 140 AHD but decline about Unit: Telerah TL m to Unit: Jangardup JN 50 m south and south-westwards The Telerah unit has slightly This is slightly undulating adjacent to the Scott Coastal Plain. undulating ridge crest zones which a terrain of <10 relief. Broadly The unit has developed form portions of local drainage di- m con- on flanked by long, deeply weathered, sandy Mesozoic vides of the Blackwood Plateau. It vex rises are very gentle slopes which with sediments; there few fresh rocks has a general elevation range of um merge are floors that either flat exposed. to 130 m AHD while internal relief are concave or and is <5 m. swampy. Both yellow duplex profiles and Jangardup along the humus podzols extensively. This unit is closely associated occurs occur flanks of the Blackwood Plateau The duplex profiles have pale with the Kingia unit and has de- as a it with the Scott Coastal brownish sand A horizon, of- veloped on deeply weathered, merges grey Plain to the south. Geologically ten with a bleached A2 horizon. The sandy Mesozoic sediments.

31 LAND RESOURCES SERIES No. 10 these areas are dominated by Swampy tracts 35 to 45 cm. Yellow duplex soils deeply weathered sandstone but of Unit: Coate CE occur on some the low rises, there are small areas of weathered along with light yellowish grey, granitic rocks and Bunbury Basalt. This unit comprises broad sand A horizons which often have There are rare surface pockets of swampy floors 0.5 to 1.5 km wide. a bleached A2 horizon with some quartzose cobbles. There are some low, broad rises ferruginous gravels. A structureless, with crests <5 above the floor of mottled clay B horizon is at 40 Yellow duplex profiles are on the m to the unit. 60 convex rises and usually have a cm. pale grey-brown sand A horizon to Coate usually comprises the Sedgelands and heaths are com- 50 cm thick and a pale brownish tracts of the drainage upper system mon, sometimes beneath a low, grey A2 horizon. The B horizon is for the Blackwood Plateau. It is set open woodland of depauperate a structureless, mottled gritty clay some 10 to 20 m below the crest of jarrah, marri and Allocasuarina and there can be dark brown to the adjoining Kingia and Telerah fraseriana. There are a few scattered black staining at the interface of the units. The elevational is from range pockets of low trees, mainly A and B horizons. Lateritic gravels 140 AHD the foot of the Dar- m at Melaleuca- preissiana, Banksia littoralis can be scattered throughout the A ling Scarp to 80 adjacent the m to and B. ilicifolia. Shrub communities horizon and occasional blocks of Scott Coastal Plain in the south- include Agonis parviceps, Pultenaea lateritic duricrust can be present. west. reticulata, Andersonia sprengelioides, Several large pockets of soils Humus podzols are widespread Lepidosperma spp., Evandra aristata, with browner hues appear to be and have a dark brown to black Scirpus nodosus, Beaufortia sparsa, related to pockets of Bunbury Ba- i ron/ orgamc. B horizon at about Leptocarpus scariosus, Kingia australis salt. These profiles have a light 1 m, often as a pan. Water tables and Mesomelaena spp. brown to light greyish brown, occur at <1 m for at least eight sandy loam A horizon on a yellow- months. ish brown to brown clay B horizon Units developed on crystalline at 40 An A2 horizon is Scattered pockets of cm. gener- orange rocks — Banbury Basalt ally present but not bleached. The earths are present with bog-iron Two units associated with clay B horizon is poorly structured pans. These earths sometimes cap are Bunbury Basalt: and has a pH of 6.5 at depth. low rises. Some duplex profiles one occupies por- have pale yellowish brown, silty tions of scarps and valley slopes, Humus podzols a are common on clay loam A horizon light yel- and the other forms undulating the broad, poorly drained inter- on a lowish brown B horizon at about plateau elements. ridge floors. These have a thick, pale grey sand A2 horizon with a black iron/organic horizon, often as a pan at 90 to 120 cm. Pale grey gritty clays form extensive an Dams are often used to irrigate crops. substrate to these profiles. Orange earths with bog-iron pans and nodules are also common on these swampy tracts. The crests and upper slopes have jarrah-marri tall woodland to open forest communities with Banksia grandis and Persoonia longifolia as a low tree understorey. A heath understorey contains an array of species such as Adenanthos cuneatus, Agonis parviceps, A. linearifolia, Bossiaea linophylla, Stirlingia latifolia and Dasypogon bromeliifolius. The more swampy tracts are dominated by a depauperate jarrah community and there can be thickets of Melaleuca preissiana and Banksia littoralis. These areas contain a dense heath of Agonis parviceps, Beaufortia sparsa, Evandra aristata and Lepidosperma longitudinale.

LAND RESOURCES SERIES No. 10 32 Scarps Downslope, these sands increase in Humus and peaty podzols are thickness while the gravels become dominant and have dark brown to Unit: Scott SC finer until deep sands are domi- black iron/ organic pans. Orange The Scott unit comprises crests nant. These soils range through earths with bog-iron pans and nod- and slopes associated with outcrops reddish yellow, light brown, yel- ules form a significant, though mi- of Bunbury Basalt. Such slopes low-brown to light brownish yel- nor, component of this soil mantle. flank parts of the Blackwood River low and commonly have a clayey Podzols occur on the dunes and valley and the McAtee Brook, a sand texture. have A2 horizons to 2 m thick over northern tributary of the.a light yellow-brown to brown fri- forests of jarrah and marn Blackwood River. There also able sand B horizon which often has are dominate this unit. There is a lower of Bunbury convolute form. some narrow outcrops tree layer (4 to 8 m) of Allocasuarina a Basalt along the Darling Scarp. fraseriana, Banksia grandis and Heath and some sedgeland com- Persoonia longtfolia. The shrub layer munities The heath Deep saprolite, usually as a red are extensive. clay derived from Bunbury Basalt, includes such species as Leucopogon species include Beaufortia sparsa, verticillatus, Macrozamia riedlei, Astartea fascicularis, is common. The soils are generally Kunzea recurva, red earths with red, friable sandy Bossiaea linophylla, B. laidlawiana, Kin gia australis and Pultenaea loam to sandy clay loam surfaces Kennedia prostrata, Hardenbergia reticulata. The sedges include comptoniana, Hovea trisperma, Evandra aristata, Scir nodosus, merging gradually to a friable red pus Clematis pubescens and Acacia Gahnia decomposita and Anarthria clay loam by about 30 cm deep. ulchella. scabra. There scattered low There can be some fragments of P are trees, weathered basalt in these horizons. mainly Nuytsia floribunda and Units of the Scott Coastal Plain Red and reddish yellow clay is Melaleuca preissiana. Dunes have a woodland of Banksia ilicifolia, found at about 45 cm. The geology of the Scott Coastal Plain basically separates the B. attenuata and Allocasuarina Marri forest communities map- are units into two classes. Units frasertana. present, with Banksia grandis and ping developed either mixed Persoonia longifolia forming low are on Slightly defined drainage a sediments aeolian sands. layer The shrub layer or tree (4 to 8 m). Unit: Cleave CV includes Boss iaea laidlawiana, Units developed mixed on This terrain reflects the Macrozamia riedlei, Hovea elliptica, sediments swampy Kennedia prostrata, K. coccinea and slight incision of the Blackwater Hakea amplexicaulis. All units on the mixed sediments unit by a system of minor streams of the Scott Coastal Plain are some 2 m deep which are flanked Undulating plateau elements swampy. Two topographical classes by long, very gentle slopes that recognized; plains and extend to the Blackwater unit Unit: Milyeannup MP are swampy up zones of slightly more defined <10 m above. Minor low rises oc- The Milyeannup unit is a gently drainage, cur, often representing the bevel- undulating upland surface forming led nose of spurs resulting from the Swampy lani part of the skyline of the Blackwood p stream incision. Plateau. Undulations often have a Unit: Blackwater BW Elements of both Archaean crys- relief of about 10 m, however, a This is a major part of the Scott talline rocks and Mesozoic greater relief range (up to 100 m) Coastal Plain. The unit de- sediments may occur and are usu- crests of the unit, where was occurs on scribed by Churchward et al. (1988) ally deeply weathered. Quartzose it is adjacent to the incision of the 'a flat, poorly drained plain, of- cobbles sometimes found, Blackwood River. as are ten with very diffuse drainage pat- strewn sparsely on the surface and Areas of this unit together terns; both seasonal or permanent there may be occasional low hum- present a general north-south zone swamps are included'. Some low, mocks of aeolian sand. towards the western limit of the generally linear dunes often occur, Humus podzols are dominant This has general concordance with east-south-east orientation, map. an with a dark brown to black iron/ with the inferred at Within the of this eleva- occurrence area map, organic pan at about 1 m. These depth of Bunbury Basalt tion from 70 AHD inland as pre- ranges m usually have a light grey sandy clay sented in Figure 3 of Wilde and to about 40 m adjacent to the coastal substrate. Some of the Al horizons Walker (1984) well being ad- dunes. as as appear to have sufficient organic jacent to outcrops of this rock along Unconsolidated sands and clays matter to classify the profiles as valleys. are extensive, some being derived peaty podzols. Yellow duplex profiles the low Lateritic duricrusts and the as- from the weathering of Mesozoic are present on rises sociated shallow, gravelly, light sediments and Archaean crystalline and have a pale grey-brown sand A horizon with bleached ho- brown to yellow-brown sands are rocks. There are also traces of a A2 rizon. The light brownish yellow extensive on the ridge crests. quartzose cobbles.

33 LAND RESOURCES SERIES No. 10 and yellow mottled sandy clay B Ms—the oldest dune phase; has calophylla occur. A dense shrub horizon is structureless. There is smooth, rounded crests and gen- layer includes Pultenaea reticulata usually some dark brown staining tle slopes. Most of the areas and Leucopogon australis. between the A and B horizons, mapped as Ms have swampy Occasional blocks of lateritic interdune tracts, delineated as Mp—dunes with crests that are of- be Mf. duricrust can present. ten higher and sharper than Ms. Heath and sedge communities In the area mapped the soils are podzolized sands that have dominate this unit and there are The soils are often podzols a Al horizon and pale some pockets of depauperate jarrah usually with a bleached A2 ho- grey a grey- brown A2 horizon which woodlands, particularly on the low rizon from 1.5 to 2.5 m thick and rises. The heath communities in- a friable brown to yellow-brown merges to a light brown to light yellow-brown, friable B horizon clude Beaufortia sparsa, B horizon (Uc2.21). Calcium car- Homalospermum firmum, Astartea bonate is usually not present from 0.5 to 1.5 m. With depth, fascicularis, Agonis parviceps, within 4 m of the surface, in the the B horizon merges to a dif- A. linearifolia, Kin gia australis and mottled light yellow, deep sub- fusely mottled light yellow, pale Leucopogon propinquus; scattered soil. In some of the well drained yellow and pale grey-brown sand (Uc4.21). Calcium carbon- low trees of Melaleuca preissiana swales there are profiles that ate, if present, is within the occur. Sedges include Gahnia have a grey-brown surface hori- rare decomposita and Evandra aristata. zon (10 cm thick) over light upper 5 m which contrasts with brown, neutral to mildly acidic the profiles of the unit described sand. By about 1 to 1.2 m, this by Churchward et al. (1988) fur- Units developed on aeolian sands profile merges to a light yellow- ther east. However, many of All units on aeolian sands of the brown and pale brown, non-cal- these profiles are comparable Scott Coastal Plain can be classified careous sand. with the Karakatta series, de- as variations of the one dune sys- scribed by McArthur and tem. Five variations are recognized. Bettenay (1960) on the Swan Woodlands of marri are Coastal Plain. Unit: Meerup M dominant with jarrah, Eucalyp- tus megacarpa (bullich) and This is of parabolic Agonis flexuosa woodlands an array E. cornuta (yate). Agonis flexuosa are dunes forming part of the coastal (Western Australian dominant and can be associated dune system. They have their pepper- mint), Allocasuarina fraseriana, with Hakea oleifolia, Allocasuarina equivalents in the parabolic dunes Banksia grandis, Leucopogon fraseriana, Banksia grandis and along the west coast of south-west- and Persoonia B. ilicifolia. The shrub layer in- Australia where they are re- dude Acacia cyclops, A. em longifolia important low tree cuneata, ferred to the Quindalup dunes are as species. A dense shrub layer Hibbertia spp., Melaleuca system by McArthur and Bettenay includes Macrozamia riedlei, thymoides, Jacksonia furcellata and (1960). In the mapped, the area Leucopogon australis, L. Xanthorrhoea preissii. Some por- dunes of the Meerup unit have prop- a inquus, Bossiaea linophylla, Hovea tions of Mp can have marri general east to east-north-east i- or elliptica, Hibbertia stellaris (star woodlands comparable with Ms. entation and transgress broad a guinea flower), Harden bergia ridge of Tamala Limestone, extend- cornptoniana, Acacia pulchella, having high frequency ing distance inland the Mc—areas a some over Xylomelum occidentale, Hakea of sharply peaked dunes. plain represented by the steep, swampy oleifolia and Hybanthus The sands be variable; Blackwater unit. Their seaward spp. appear to much less calcareous flank is marked by steep slopes and some are than described for this unit in local cliffs developed in the under- Mf—interdune flats which, as Churchward et al. (1988). Some lying Tamala Limestone and ferru- mapped, often dominated by are profiles have pale grey-brown ginous facies of Mesozoic The soils a swampy tracts. are A2 horizon and light yellow sandstones. podzols with dark brown to a a to yellow-brown B horizon at 0.5 black B horizon at about 0.75 to The dune complex first to 1.0 Low amounts of was re- 1.25 beneath bleached sand m. car- ferred to the Meerup soil m a bonate be present at about as asso- A2 horizon. can ciation by McArthur and Clifton 2 m. In this profile there is or- (1975) and further details of this ganic enrichment of the surface unit have been presented by There are woodlands and 10 cm. Other profiles have light Churchward et al. (1988). They rec- thickets of Melaleuca preissiana, brownish grey sand to 10 cm, ognized six subdivisions but only Banksia littoralis and Agonis merging to pale brown or light five are delineated on the present juniperina (native cedar). Some yellowish brown sands by map. Beach ridges (My) do not pockets of Eucalyptus cornuta, 30 cm. Slight to light calcium occur along this section of the coast. E. megacarpa and Eucalyptus carbonate, sometimes as sand

LAND RESOURCES SERIES No. 10 34 grains and general effervescence composition. Stone lines in the A Murray-Hotham catchment, is to acid, appears at about 40 to horizon of the duplex soils are corn- dominated by long, gentle slopes 50 cm. mon, suggesting that it has devel- (<50) that extend down from low, oped in transported medium. The often flat-crested hills towards The vegetation comprises a a nar- dense shrub layer and coastal upper terrace has brown to yellow- row alluvial valley floors. Erosional heaths. The dwarf form of brown clayey sands while the lower scarps (breakaways) as narrow comprises greyish brown flanking of these Agonis flexuosa is common along terrace to zones some me- with Olearia axillaris, Jacksonia brownish grey silty loams to silty sas are the steepest parts of the ter- clay loams. Unlike other valley furcellata, Hemiandra pun gens rain. the units, (snake bush), Spyridium the Noombling unit, as an erosional Vegetation is mainly open marri globulosum and Scaevola tract, can in places extend across spp. forest, with Banksia grandis an as divides from one valley to the next. important element of the low tree layer. Eucalyptus rudis (flooded Mu—mobile sands that are pale yel- Although there are scattered low to light yellow-brown and gum) dominates the terraces of the outcrops of granitic rocks and are often low to very low in valley floors. dolerite dykes, kaolinitic clay de- calcium carbonate. Unit: Balingup BL rived from these rocks forms a frequent substrate to the soils. Lateritic associated Units with drainage This unit, defined by Finkl duricrusts, and associated gravels lines (1971), represents tributary valleys and sands, cap the mesas and are Drainage lines form three broad of the Blackwood River system. seen as remnants of a once, more groups of units. There are those on These valleys are 2 km wide and extensive, deeply weathered land the Darling Plateau (crystalline from 60 to 100 m deep; their flank- surface that has been stripped from rocks), the Blackwood Plateau ing slopes are commonly between slopes and local divides. (mainly on Mesozoic sediments) 100 and 25° but can be as low as 6°. and the Scott Coastal Plain. The surface of this unit appears to The Noombling unit is drained be smoother than the Bridgetown by the Blackwood River and is lim- Units associated with drainage unit. The floors are broadly concave ited to the extreme north-eastern lines in the Darling Plateau, on to flat. There can be local swamps corner of the area. It ranges from crystalline rocks and a shallow stream channel can 180 to 280 m AHD and local relief be flanked by terrace. is about 50 m. This broad group of units can be a narrow subdivided There are occasional outcrops of into major and minor The soil mantle is dominated by valleys. Major valleys have floors gneiss, migmatite and granite but duplex profiles. The presence of with well defined drainage chan- these rocks. have generally been stone lines of mixed composition at nels, valleys have deeply kdaohmze to form a wide- mantle.tracts.hori-minor swampy the interface of the A and B s read substrate to the soil zons, indicate the colluvial origin Gradational profiles Major valleys are more of many of the surface horizons. common than duplex profiles and Unit: Bridgetown BT red hues are more common than Yellow duplex profiles dominate yellow. Yellow duplex profiles with granite. These have pale This unit, defined by Finkl (1971) areas on a bleached A2 horizon and mot- grey-brown to light yellowish represents the southern parts of the a a tied horizon brown, hard-setting sandy loam trunk valley of the Blackwood River structureless B are on to the floor; yellow-brown loamy sand A horizon and have incised into the Darling Plateau. valley can sandy loams the A2 horizons with bleach Elements of it extend westward are on narrow ter- a spotty (Dy3.61). The clay B horizon be from about 15 km east of races. can whole-coloured slightly mottled. Bridgetown to where the river or Open forests and tall woodlands Sometimes it is structured. The flows through the Darling Scarp. In not of marri, with some jarrah, are corn- deep subsoil usually has neutral the mapped, the unit has a area a mon. Banlcsia grandis and Persoonia H of ID relief 120 to 150 m. Slopes are longifolia are prominent in the low • steep (to 30°) and irregular be- are tree layer. There may also be some Red duplex profiles (Dr2.21) are of outcrops of gneiss, cause Acacia acuminate (jam) and Eucalyp- much less common and generally migmatite and granite. Colluvium tus loxophleba (york gum) but relate to the presence of a dolerite extensively, occurs sometimes as E. rudis woodlands dominate the dyke. The sandy loam to sandy clay slumps. valley floor, with some Allocasuarina loam A horizon is usually light red- huegeliana. The soil mantle is a complex dish brown with a pale reddish brown A2 horizon. The clay B ho- array of gradational and duplex Unit: Noombling NB profiles. Red hues are dominant, rizon is usually moderately struc- suggesting the greater overall influ- This terrain, described by tured but not mottled and the pH ence of rocks with mafic (i.e. basic) McArthur et al. (1977) for the is neutral.

35 LAND RESOURCES SERIES No. 10 The crests of mesas are domi- pentadenia, Bossiaea linophylla, downstream with the Warren unit nated by gravelly pale brown to Trymalium spathulatum, Chorizema and upstream with the Wheatley yellow-brown sands usually with ilicifolium (holly flame pea), Hovea unit. lateritic duricrust at <30 cm. There elliptica and Hardenbergia may be some areas of deeper sands comptoniana. Red earths (Gn2.12) are domi- with much pisolitic lateritic gravel. nant and often have a gravelly Unit: Warren WA sandy loam A horizon. There are The vegetation is dominated by significant of red duplex This unit comprises valleys that areas pro- tall marri woodlands with Eucalyp- files and gravelly duplex soils that from 60 to 100 deep and from tus wandoo (wandoo) and some are m have brownish hues (7.5YR). jarrah. Small pockets of woodland 0.75 to 1 km wide. Slopes range ffrom but b low comprising low trees of 10° to 20° can e as Tall, open karri forests are domi- 5°. The floors be occupied Allocasuarina huegeliana, Eucalyptus as can nant but marri becomes more im- by terrace. The few out- loxophieba and Acacia acuminata may a narrow portant to the north-west of usually of rocks be found by rock outcrops. Euca- crops are gneissici i Manjimup probably due to the lyptus rudis woodlands dominate and the slopes are usually smooth lower rainfall. The low tree layer andpartially mantled colluvium the valley floors along with some includes Banksia grandis, Agonis Melaleuca rhaphiophylla. The laterite arising from the kaolinitic clay de- flexuosa and Allocasuarina decussata. rved from the underlying rocks. capped crests have tall jarrah wood- i i There is a dense shrub layer of Trymalium floribundum, Acacia lands with a dense understorey This unit occupies parts of the pentadenia, Bossiaea laidlawiana, which includes Dryandra sessilis,Donnelly River system and valleys ,Chorilaena quercifolia and Hovea Macroza mia riedlei and Xanthorrhoea of adjacent streams. It is upstream elliptica. Agonis . and preissii. of the Donnelly unit and down- juniper tna Oxylobium lanceolatum the stream from the Lefroy unit. are on Unit: Donnelly DO narrow terraced valley floors. Red earths (Gn2.12) the This unit comprises valleys 100 are dominant soils. There Unit: Wheatley WH to 140 deep and 1 to 2 km wide, are some m yellow earths and red and yellow and which have slopes of 15° to 20° This unit comprises valleys that duplex soils, also brown sand y but can be as low as 6°. The floor are from 20 to 40 m deep and loams are to be found on the nar- can be occupied by a narrow ter- flanked by smooth slopes of 5° to row terrace. race. Although there are scattered 10°; there are local steeper facets to The valleys have outcrops of gneissic or migmatitic Tall, open karri forests are domi- 15°. swampy channels rocks, the slopes are generally nant but marri is more important floors terraced by stream incised from smoother than those of the as rainfall decreases northward. The 1 to 2 m. Bridgetown unit. They are mantled low tree layer is mainly Banksia The associated gneissic and by colluvium which overlies grandis, Agonis flexuosa and migmatitic rocks have been kaolinitic clay derived from the Allocasuarina decussata. The shrub extensively kaolinized depth. There weathering of gneissic rocks. layer is dense and important at spe- few outcrops of fresh rocks. cies include Acacia pentadenia, are The unit occupies the lower Bossiaea linophylla, Hovea elliptica, of the Donnelly River and course Clematis pubescens and Chorizema neighbouring associated of the Lefroy unit in valleys situ- streams ilicifolium. with the Darling Plateau, just be- ated west, south, and south-east of Manjimup and Pemberton. fore they pass through the Darling Unit: Lefroy LF Scarp. This unit consists of major val- The soils of the flanking slopes have gradational profiles. Red hues Red earths (Gn2.12) are the leys from 40 to 60 m deep. The (Gn2.12) but there dominant profiles but there are smooth flanking slopes range from are common are that yellow. The surface some yellow earths as well as red 10° to 200; some (to 30°) are more some are horizon is greyish brown, and yellow duplex soils (Dr2.2, irregular and occur in local ero- a gray- loam Dy3.6). Brown sandy loams occupy sional alcoves. The floor is occupied elly sandy which merges at 40 50 brownish red the narrow terraces. by a narrow terrace and there is a to cm to a or clearly defined stream channel. brown light clay. Some duplex pro- Tall, karri forests domi- files, both red yellow open are Deep kaolinitic clays form an ex- or types, can nant but marri becomes important also The tensive substrate to the soils so that occur. swampy terraces rainfall decreases towards the as outcrops of the underlying gneissic generally have grey-brown to yel- northern limit of the unit. A low low-brown sands sandy loams. rock are infrequent, to tree layer is mainly represented by There are some areas with profiles Allocasuarina decussata, Agonis This unit occurs along valleys having a pale yellow-brown sandy flexuosa and Banksia grandis. There west of Manjimup and south to loam A horizon on a mottled is a dense shrub layer of Acacia south-west of Pemberton. It merges brownish yellow clay B horizon.

LAND RESOURCES SERIES No. 10 36 Tall, open forests of karri and extensive plant communities. Low floor and have an acidic to neutral marri are dominant. There are scat- tree species include Banksia grandis, pH. tered low trees of Allocasuarina Leucopogon verticillatus and Persoonia Marri woodlands to forest decussata, Banksia grandis, Persoonia longifolia. Some tall woodlands open communities dominant, particu- longolia and Agonis flexuosa, and dominated by wandoo are a appear as larly the slopes, while Eucalyp- dense shrub layer of Acacia the rainfall declines eastwards. The on tus rudis woodlands the pentadenia, Bossiaea laidlawiana, shrub layer includes Bossiaea occupy floors. Melaleuca preissiana and Trymalium floribundum, Chorilaena linophylla, B. ornata, Podocarpus Banksia littoralis thickets in quercifolia and Hovea elliptica. Euca- drouynianus, Hovea trisperma and occur swampy areas. lyptus megacarpa, E. patens (Swan Xanthorrhoea preissii. Thickets of River blackbutt), Agonis juniperina, Gas trolobium bilobum (heart-leaf Unit: Strachan ST Oxylobium lanceolatum and poison) in the valley of the occur This unit consists of valleys Melaleuca preissiana Perup River. Eucalyptus rudis wood- grow on <20 deep, with smooth, gentle lands dominate the terraces and m swampy terraces. slopes (3° 8°) and terraced floors. there thickets of Melaleuca incana to are Country rock is mainly granite. The Unit: Wilgarup WL (grey honey-myrtle), M. viminea and unit is represented by the valley of These valleys have considerable Banksia littoralis. the Tone River, east and west of morphological variation. They Unit: Yerraminnup YE the Strachan mill site (ref: MG range in depth from 40 to 100 m This unit comprises valleys in the 503930); and a short length of the but are commonly from 50 to 70 m. Wilgarup River valley Darling Plateau with a depth of 20 near This considerable range is generally Morallup (ref: MH422023), where to 40 m, but occasionally to 50 m. related to broad but localized un- there low elevations The slopes are 5° to 8°; occasion- are some on dulations of the adjacent plateau the plateau surface bordering the ally to 25°. Broad valley floors have surface. The short flanking slopes valley. sinuate channel set of the Wilgarup valleys are gener- a stream some ally smooth and gentle (from 5° to 3 m into a terrace. Yellow duplex profiles are dominant and have gravelly, light 8°) but may be steeper (to 20°), The Yerraminnup unit merges a very loamy horizon when associated with deeper val- downstream to the Catterick unit grey-brown sand A with bleach. The yellow- ley tracts. Here, slopes are irregu- and upstream to the Wilgarup unit. a spotty brown clay B horizon is poorly lar and much country rock is ex- The unit is more common in the structured and the soil reaction is posed. The upper limits of the unit drier parts of the mapped area, mildly acidic at depth. are marked by exposures of lateritic appearing some 15 km east of duricrust. Terraces occupy the val- Manjimup along such streams as Tall woodlands and often forests ley floor. the Yerraminnup and Perup rivers, of jarrah and marri are dominant. The geology of this unit is domi- Granite is the dominant country Associated species include Banksia grandis, Persoonia longifolia, nated by granitic rocks which are rock while dolerite occurs as scat- Podocarpus drouynianus, Leucopogon occasionally intruded by dolerite tered dykes. These rocks are ex- verticillatus, Bossiaea linophylla and dykes. posed locally on steep slopes; more usually they covered by thick AgonisA parviceps. Eucalyptus rudis, The Wilgarup unit be are a can kaolinitic mantle. Astartea fascicularis, Melaleuca incana present upstream of the Warren and M. viminea are important on the unit and is best represented along Yellow duplex profiles are com- terraced floors. the lower courses of the Wilgarup, mon. These have a pale brown to Perup and Warren Rivers, grey-brown loamy sand to sandy Minor valleys loam A horizon and A2 horizon Red and yellow duplex soils an Unit: Catterick CC are that is sometimes bleached. The The A2 horizon usually common. mottled, weakly-structured clay B This unit represents minor val- has a spotty bleach and stone lines horizon is acidic to neutral at depth leys the Darling Plateau at the interface of the A and B ho- on (Dy3.61, D3.62). Red duplex profiles (Churchward and McArthur 1980) rizons indicate the colluvial origin and red earths associated with downstream from the Carbunup of materials forming the A horizon, are mafic rock outcrops or subcrops. unit. Such valleys are generally The B horizon often has a moder- Variable amounts of ferruginous about 20 deep but occasion- ate grade of blocky structure, m are coarse gravels in the A hori- ally 30 and flanked by 3° to is either whole-coloured dif- are present m are or Sometimes there is line 8' slopes, although slopes fusely mottled and the subsoil is zon. a stone some in the A2 horizon that comprises be to 15°. The flat and usually mildly acidic to neutral. The may up clasts of country rock and vein floors clearly terraces have yellow-brown sand to swampy are more Yellow duplex profiles with defined than the valley floors of the grey-brown silty barns, quartz. a bleached sandy loam A2 horizon Carbunup unit. Occasionally the Tall woodlands and open forests, and a mottled, coarsely structured drainage is defined in shallow dominated by marri, are the most clay B horizon are on the valley channels.

37 LAND RESOURCES SERIES No. 10 Granite rocks dominate in these orange earths with bog-iron pans cornptoniana, Bossiaea laidlawiana, areas and are usually weathered to at <1 m. B. linophylla and Clematis pubescens. a deep kaolinitic saprolite. A few Thickets of Agonis juniperina, outcrops of granite and dolerite (as Tall woodlands and open forests Banksia verticillata and Oxylobium of jarrah dominant. Banksia dykes) can occur in the rare steeper are lanceolatum, with some Eucalyptus grandis and Persoonia ion slopes. are rudis are on the swampy valley the low species along common tree floors where there is also a dense The smooth flanking slopes gen- with Allocasuarina fraseriana and shrub layer of Agonis parviceps and erally have yellow duplex soils with Xylomelum occiden tale on some of Lepidosperma longitudinale. a very gravelly, pale grey-brown the deep sands. Melaleuca preissiana loamy sand A2 horizon which is and Banksia littoralis are associated Unit: Yanmah YN Shrub sometimes bleached. Red grada- with swampy parts. species This unit comprises minor val- tional and red duplex profiles indi- include Podocar drouynianus, pus leys of about 20 m depth, with flat cate outcrop subcrop of Agonis parviceps, A. linearifolia, an or to broadly concave, poorly drained dolerite dykes on the few steeper Pultenaea reticulata and valley floors. The smooth flanking slopes. Hypocalymma angustifolium. slopes are usually 3° or less. Gra- Light yellow-brown sands, Unit: Pemberton PM nitic and gneissic rocks, deeply kaolinized, form sometimes very gravelly, may also a common mantle the valley slopes blending These valleys are 20 to 40 m deep substrate but exposures of fresh with podzols in the valley floor, and generally have flat or very rock are not common. gently sloping floors. There is little Most of the floors are, however, Yellow duplex soils domi- channel development. Flank- are dominated by yellow duplex soils or no nant. These have pale grey-brown ing slopes have gradients of 3° to a having a bleached A2 horizon. gravelly sand to loamy sand A 10°. Some slopes steeper (to Grey-brown to orange earths with are horizon, sometimes with bleached 15),° usually in erosional alcoves. a bog-iron pans are often present A2 horizon. The clay B horizon is along- the swampy drainage axis. mottled and structureless. Occa- This unit occupies the upper sional blocks of laterite Open forests of jarrah and marri reaches of many valleys west and may occur at the interface of the A and B ho- communities dominant the south of Manjimup, mainly up- are on rizons. The duplex profiles domi- slopes. Woodlands the floors stream of the Wheatley unit. Many on nate the valley slopes and there include Eucalyptus rudis and pock- of these valleys terminate through be of deep, of Melaleuca preissiana and relatively steep slopes to the upland may some areas very ets gravelly, light yellow sands. These Banksia littoralis. units, Bevan or Crowea. Occasion- soils into light yellow sands ally they merge upstream to broad merge downslope, the fringes of the Unit: Carbunup CB swampy tracts such as the Yornup on unit, valley floor, and then to podzols The Carbunup unit consists of and humus podzols in the valley minor valleys on the Darling Pla- The country rocks rarely out- floor. Some yellow duplex soils teau that are <20 m deep and crop. They are generally covered by may occur on the floors as well as flanked by long gentle slopes of a deep kaolinitic mantle. pockets of orange-brown or grey- <5°. They have broad swampy brown earths with bog-iron pans. Red, and yellow earths floors. Shallow stream channels are some with gravelly sandy loam Tall woodlands and open forests not common. a to sandy clay loam surface horizon, of marri, with some jarrah, are These valleys occur in areas of are most extensive. There are areas dominant. Karri is an important granite but exposure of fresh rock of red duplex profiles which also associated species and increases is rare. There is a general thick have a light brown, gravelly sandy with rainfall to the south and west substrate of kaolinized country loam A horizon. Some of these pro- of Manjimup. The low tree layer is rock. files have an A2 horizon. Humus often Banksia grandis, Persoonia podzols and orange and grey- longifolia and sometimes Agonis The slopes usually mantled flexuosa are brown earths occur on the valley and Acacia pentadenia. A by deep, gravelly, light yellow- floor, dense shrub layer can include brown sands, sometimes with Bossiaea linophylla, B. laidlawiana, lateritic duricrust at 1 to 2 m. The Tall, open karri forests with B. ornata, Acacia myrtifolia, A. la teritic gravels become finer some marri are usual for this unit; pulchella and Trymalium floribundurn. downslope, giving way to deep, sometimes marri is dominant. A The swampy valley floor may have light yellow-brown sands on the low tree layer of Allocasuarina a low woodland of Banksia littoralis lower slopes and portions of the decussata, Agonis flexuosa, Banksia and B. verticillata, Agonis juniperina floor. Podzols are dominant on the grandis and Persoonia longifolia oc- and Oxylobium lanceolatum in higher floors with some humus podzols as curs. The shrub layer includes rainfall areas, along with many well as some pockets of sandy Hovea elliptica, Harden bergia sedges and reeds.

LAND RESOURCES SERIES No. 10 38 Units associated with drainage Unit: Jalbaragup JL swampy tracts. Grey-brown silty lines in the Blackwood Plateau, loam silty clay barns the This unit comprises valleys in- to occupy mainly on Mesozoic sediments lower terrace. cised 20 to 40 m into the Blackwood As with the Darling Plateau, Plateau. Stream channels are gen- Open marri forests are common, erally about 1 deep and particularly the slopes, with units of the drainage elements on m are on flanked by The Banksia grandis and Persoonia the Blackwood Plateau can be cat- a narrow terrace. slopes 5° to 12°. longifolia. Eucalyptus rudis egorized as occurring in major (well are appears the terraces along with Melaleuca defined) or minor (swampy) val-The sedimentary rocks forming on preissiana, Banksia verticillata, leys.theBlackwood Plateau are not usu- B. littoralis and Agonis flexuosa. A ally exposed and the slopes are dense heath layer includes Agonis mantled by kaolinitic saprolite, Major valleys parviceps, Kin gia australis, Bossiaea lateritic gravels and sand. linophylla and Hovea elliptica. Unit: Blackwood BK Yellow duplex profiles are corn- Minor valleys MOJA on the slopes. These have a This unit comprises major val- dark grey-brown loamy sand A Unit: Bidella BD leys 40 to 60 deep with flanking m horizon which merges at depth to slopes ranging from 8° to 12°; This unit comprises minor val- occa- a pale brownish grey A2 horizon sionally steep 20°. A system leys on the Blackwood Plateau up- as as overlying a mottled structureless of two terraces of variable width stream from the more deeply in- sandy clay B horizon. There may cised valleys of the Jalbaragup unit. occupies the floors and this system be lateritic gravels in the A some The valleys are usually <20 m deep is trenched (to 4 m deep) by the horizon. The valley floor narrow and have broadly concave, swampy sinuous channels of major trunk has grey-brown silty loams, with floors. The flanking slopes are gen- streams, earths and yellow- some orange erally <30 and are cut into brown clayey sands. The Blackwood unit represents kaolinized Mesozoic sediments of the valley of the Blackwood River Marri forest communities domi- the Blackwood Plateau. They are mantled by lateritic gravels and incised into the undulating surface nate these areas but there is some of the Blackwood Plateau. jarrah. Low trees of Banksia grandis sands. Sandstones exposed along the and Persoonia longifolia the are are on A frequent soil toposequence in slopes but of the slopes. Along the floors and steeper on most narrow this unit begins upslope with yel- gentler grades the rock lower slopes, Eucalyptus rudis country is is low duplex profiles having mantled by lateritic detritus includ- associated with Banksia verticillata a very gravelly, pale grey-brown sand Al ing both sand and gravel with and Agonis flexuosa. A dense shrub scat- horizon and gravelly pale tered blocks of duricrust and layer includes Bossiaea linophylla„ a very brown-grey to A2 horizon kaolinitic sandy clay saprolite. B. laidlawiana, Agonis parviceps and grey on mottled sandy clay B horizon at Hovea elliptica. a about 35 to 50 Further The dominant soils of the slopes cm. Unit: Barlee BR downslope the A horizons deepen are yellow duplex profiles with a and humus i3odzols are the domi- pale brownish A horizon and This unit comprises valleys to grey nant soils with dark organic sand sometimes bleached A2 horizon 20 deep with flanking slopes of a m Al horizons merging at depth to over a pale yellow, sandy clay B about 3°. The broad valley floors light pale grey sand A2 horizons horizon, which is usually mottled usually have two terraces, and the and compact black iron/organic and structureless. There can also be stream channel is about 2 m deep. sand B horizons at 70 to 100 cm. pale yellow sands on some of the These valleys incised into the Beneath this are light grey sandy more gentle slopes which merge to are Blackwood Plateau. Flanking slopes clays. podzols downslope. The upper ter- kaolinized Mesozoic sedimen- races have light yellow-brown to are On the slopes of tary rocks d tl d b upper some brown clayey sand to sand and the roc an are mane y toposequences, pale yellow sands lateritic detritus. lower terraces are usually grey- have a slightly developed A2 hori- brown silty barns. Yellow duplex profiles dominate zon containing ferruginous gravel. the slopes. These have a pale grey- These give way to podzols on mid On the slopes there marri are brown loam A horizon with a well to lower slopes and thence to hu- woodlands closed with woodlands developed A2 horizon. Ferruginous mus podzols on the valley floors. of Eucalyptus rudis the on terraces. gravels occur frequently. The B Some yellow duplex profiles with Low trees include Banksia grandis, horizon is a mottled, structureless, a pale brown silty loam to brown Persoonia longifolia and Allocasuarina gritty clay at about 35 to 45 cm. The silty clay loam A horizon over pale fraseriana the slopes and Agonis on soils on the upper terraces are yel- to light yellow-brown sandy clay B flexuosa and Banksia verticillata on low-brown sands to clayey sands. horizon, occur on the valley floors the terraces. Humus podzols are found in local as well.

39 LAND RESOURCES SERIES No. 10 Open forests to tall woodlands Jasper largely represents the en- of jarrah and marri dominate the trenchment of the lower Barlee slopes, with Banksia grandis, Brook and the Donnelly River, and Persoonia longifolia and Allocasuarina associated minor tributaries, as they fraseriana as the lower tree species. traverse the swampy plain (the Banksia littoralis and B. verticillata Blackwater unit). Included is that appear on the valley floors along stretch of the Donnelly River which with Melaleuca preissiana. A dense passes through the belt of coastal shrub layer includes Agonis dunes. parviceps, Pultenaea reticulata, The lower has Podocar drouynianus and terrace grey- pus brown to light yellow-brown silty Dasypogon hookeri. barns to silty clay barns. The up- Unit: Layman LY per terrace is mainly light yellow- brown clayey sands but This unit includes valleys that some podzols present. Humus <20 deep and also have are are m podzols the broadly flat and occasion- occur on more swampy concave, parts. ally swampy, gently sloping tracts. Such areas are dominated by Marri forests occur, with a low colluvial sands but there can be tree layer of Banksia grandis, alluvial elements. The Layman unit B. verticillata, Persoonia longifolia and often lies next to the Blackwood Agonis flexuosa. A dense shrub layer River where its roughly curvate of Podocarpus drouynianus, Bossiaea shape suggests that some portions linophylla, Kin gia australis and of the unit, at least, represent an Adenanthos obovatus is present. early phase of the Blackwood River system before it was incised. The unit ranges from 60 to 80 m AHD. The unit is dominated by deep sand profiles. There are light brownish yellow sands on the better drained parts. These merge downslope with podzols and eventually humus podzols in the more swampy portions. Tall woodlands and low, open forests are common. Jarrah is the dominant tree, but there is some marri. Banksia grandis, Allocasuarina fraseriana and Nuytsia floribunda form a low tree layer. Banksia littoralis and Melaleuca preissiana are in the more swampy parts. A dense shrub layer with a large range of species is present.

Units associated with drainage lines on the Scott Coastal Plain There is only one major valley unit on the Scott Coastal Plain. It has a well defined channel. Unit: Jasper JA

The unit comprises a trench <10 m deep. There are two terraces; some portions of the upper terrace can be swampy.

LAND RESOURCES SERIES No. 10 40 The author wishes to thank those colleagues whose many comments Acknowledgements and criticisms were of assistance in the preparation of this manuscript, in particular Geoff Dimmock, Jim Dixon, Brian Purdie and Peter Tille.

41 LAND RESOURCES SERIES No. 10 Baxter, J.L. (1977). Heavy mineral sands deposits in the Perth Basin. Western Australian Geological Survey, Mineral Resources, Bulletin References 10. Bettenay, E., Russell, W.G.R., Hudson, D.R., Gilkes, R.J., and Edmiston, R.J. (1980). A description of experimental catchments in the Collie area, Western Australia. Division of Land Resources Management Technical Paper No. 7, CSIRO, Australia.

Bureau of Meteorology (1965). Climatic Survey. Region 16 - Southwest Western Australia. Government Printer, Melbourne.

Churchward, H.M. and Batini, F.E. (1975). Soil pattern and resources utilization in the Wungong catchment, Western Australia. Division of Land Resource Management Series No. 1, CSIRO, Australia. Churchward, H.M. and McArthur, W.M. (1980). Landforms and soils of the Darling System, Western Australia. In 'Atlas of Natural Resources, Darling System, Western Australia'. Department of Conservation and Environment, Western Australia. Churchward, H.M., McArthur, W.M., Sewell, P.L. and Bartle, G.A. (1988). Landforms and soils of the south coast and hinterland, Western Australia. Northcliffe to Manypeaks. Division of Water Resources, Divisional Report 88/1, CSIRO, Australia. Cope, R.N. (1975). Tertiary epeirogeny in the southern part of Western Australia. Geological Surveys Annual Report 1974: 40-46, Western Australia. Finkl, C.W. (1971). Soils and geomorphology in the middle Blackwood River catchment, Western Australia. Ph.D. Thesis, University of West- ern Australia, Nedlands, Western Australia (unpublished). Finkl, C.W. and Fairbridge, R.W. (1979). Paleogeographic evolution of a rifted cratonic margin, S.W. Australia. Palaeogeography, Palaeoclimatology, Palaeoecology 26: 221-52. Gentilli, J. (1972). 'Australian climatic patterns'. Nelson, Melbourne. Jutson, J.T. (1934). The physiography of Western Australia. Bulletin of Geological Survey, Western Australia. No. 95. McWhae, J.R.H., Playford, P.E., Linder, A.W., Glenister, B.F. and Balm, B.E. (1958). The stratigraphy of Western Australia. Journal of the Geo- logical Society of Australia 4: 161. McArthur, W.M. and Bettenay, E. (1960). The development and distribution of the soils of the Swan Coastal Plain, Western Australia. Divi- sion of Soils, Soil Publication 16, CSIRO, Melbourne. McArthur, W.M. and Clifton, A.L. (1975). Forestry and agriculture in relation to soils in the Pemberton area of Western Australia. Division of Soils, Soils and Land Use Series No. 54, CSIRO, Australia. McArthur, W.M., Churchward, H.M. and Hick, P.T. (1977). Landforms and soils of the Murray River catchment of Western Australia. Di- vision of Land Resource Management Series No. 3, CSIRO, Australia. Mulcahy, M.J. (1973). Landforms and soils of north-western Australia. Royal Society Western Australia Journal, 56: 16-22. Munsell Soil Color Charts (1954). Munsell Color Company, Inc. Balti- more, Maryland, United States of America. Northcote, K.H., Bettenay, E., Churchward, H.M. and McArthur, W.M. (1967). Atlas of Australian Soils — explanatory data for Sheet 5, Perth- Albany-Esperance area. CSIRO, Melbourne University Press.

43 LAND RESOURCES SERIES No. 10 Northcote, K.H. (1979). 'A factual key for the recognition of Australian soils'. 4th Edition. Rellim Technical Publications, Glenside, South Aus- tralia. Northcote, K.H., Hubble, G.D., Isbell, R.F., Thompson, C.H. and Bettenay, E. (1975). 'A description of Australian Soils'. CSIRO, Melbourne. Playford, P.E., Cockbain, A.E. and Low, G.H. (1976). Geology of the Perth Basin, Western Australia. Western Australian Geological Survey Bulletin 124. Stace, H.C.T., Hubble, G.D., Brewer, R., Northcote, K.H., Sleeman, J.R., Mulcahy, M.J. and Hallsworth, E.G. (1968). 'A handbook of Austral- ian soils'. Rellim Technical Publications, Glenside, South Australia.

Stephens, C.G. (1946). Pedogenesis following dissection of lateritic re- gions in southern Australia. Bulletin No. 206, CSIRO, Melbourne. Taylor, M. (1971). The Kirup Conglomerate. An unusual sedimentary remnant in the south-west of Western Australia. M.Sc. Thesis, Uni- versity of Western Australia, Nedlands, Western Australia (unpublished). Trendall, A.J. (1975). Precambrian. In 'Geology of Western Australia'. Geological Survey of Western Australia, Memoir 2: 25-32. Wilde, S.A. and Walker, I.W. (1984). Pemberton-Irwin Inlet, Western Australia. 1:250,000 Geological Series Explanatory Notes, Geological Survey of Western Australia

LAND RESOURCES SERIES No. 10 44 Two map sheets accompany Appendix 1 this publication

45 LAND RESOURCES SERIES No. 10