East Devon Research Articles

Tertiary lateritic weathering in Devon, England, and the Palaeogene continental environment of South West England

The plateau deposits of East Devon contain a variety of residual deposits including non-indurated kaolinitic weathering profiles and silcretes. These reflect a complex pedological, diagenetic and geomorphological history which began with the emergence of the post-Chalk land surface at the end of the Cretaceous. During the Palaeocene, lateritic weathering of the Chalk led to the formation of kaolinitic residual flint gravels which are up to 10 m thick over much of the East Devon tableland. These deposits show a variety of deep weathering profile morphology, but well differentiated lateritic weathering profiles are preserved in irregular deep pockets on Chalk. Where resting directly on Albian sediments the residual gravels are thought to represent the response of earlier profiles developed on Chalk to continued pedogenesis and diagenesis once the Chalk had been completely removed. Locally, late silicification of the weathering profile formed silicretes. Cenomanian-Albian calcarenites and arenites have been decalcified and kaolinised to considerable depths beneath the gravels where a protective Chalk capping is absent. In areas adjacent to the Sticklepath-Lustleigh Fault Zone destruction of the Palaeocene weathering mantle was accomplished by late Middle Eocene times when new weathering profiles were established on newly exposed Upper Palaeozoic rocks. These younger profiles were subsequently eroded and redeposited in deep tectonic basins along major wrench fault zones. This phase of erosion and sedimentation was accompanied by a climatic change which is reflected by changes in profile morphology and clay mineralogy with time. The oldest Palaeocene profiles are mature, took >10 7 years to form and developed in a tropical climate, whereas profiles dating from the Lower Eocene onwards are immature, took ≈10 6 years to form and developed in a sub-tropical to temperate climate.

Program Presentations at the 1982 Annual Scientific Meeting of the American Society of Clinical Hypnosis

Abstract Preceded by the Annual Workshops of the American Society of Clinical Hypnosis, which will be held in Denver, Colorado, from October 25–26, 1982, the Annual Scientific Meeting will convene during October 28–30, 1982. Detailed information about both programs may be obtained from the Society's central office (2250 East Devon Avenue, Suite 336, Des Plaines, Illinois 60018). The papers which will be presented at the Scientific Meeting are listed below. Specific times and dates will be available in the official program, which will also note any last-minute changes.

The use of specific conductance in studies of natural waters and soil solutions / Emploi de la conductance spécifique dans les études des eaux naturelles et des solutions dans le sol

ABSTRACT Specific conductance (SC) is widely used as a measure of mineral salt concentration and a variety of models have been employed which relate SC to total dissolved solids (TDS) and individual ionic concentrations. This paper attempts to evaluate several models and highlights two major problems associated with them from analysis of water samples collected from two small catchments in East Devon and North Warwickshire. First, the presence of dissolved organic material, at the levels encountered in soil solutions, may seriously affect the SC/TDS relationship and will often be an undetected component of dissolved load. Secondly, the low pH of some water samples is shown to affect those models which calculate SC on the basis of individual ionic concentrations. This results from high H+ ion levels and associated increased solubility of other ions, such as Fe3+, Al3+ and Mn2+ which are not normally determined in water quality studies.

Planning Policies and Development Control in the Sussex Downs AONB

Local planning authorities in England and Wales are responsible for the care and administration of Areas of Outstanding Natural Beauty (AONBs). Since 1956 thirty three AONBs have been designated, including some of the best known parts of the countryside such as the Cotswolds and Chilterns, the Cornish coast and Gower peninsula. 1 The statutory purpose of AONB designation is to preserve and enhance natural beauty, but there are no special planning arrangements for AONBs as there are for their counterparts, the national parks. This means that 'preservation' is generally advanced through the ordinary development control process and 'enhancement' through the use of grant aid for such work as tree planting and the reclamation of eyesores and dereliction. In spite of the fact that AONBs now cover nearly 10 per cent of England and Wales there has been virtually no monitoring of their success or failure, although it has been claimed that the designation has enabled substantial new developments to be steered away from sensitive areas of countryside.2 This is probably true, but ultimately it may be the gradual accretion of minor developments that will make more impact on the beauty of these areas than a few major schemes would have done. In 1978 the Countryside Commission instituted a major reappraisal of AONBs. To this end a Discussion Paper3 was produced to which organisations and individuals were invited to respond. In addition the Commission appointed Mr K. S. Himsworth to undertake a study of the effectiveness or otherwise of the designation. His report is expected to be published in 1980/81. The Commission's work will not, however, be sufficiently detailed to include analysis of the day-to-day workings of development control in AONBs and whether designation has had any effect on planning applications received or decisions reached. This paper attempts to throw some light on this topic by outlining the results of a study in East Sussex of the relationship between development control and strategic planning, as revealed through an analysis of planning application data. The study area included part of the Sussex Downs AONB and in this way was similar to some earlier research undertaken by Blacksell and Gilg in East Devon.4 The paper ends with a comparison of the findings from East Sussex and East Devon which tend towards somewhat different conclusions.

Modelling nitrate behaviour in a small catchment, east Devon, UK

Stream water samples have been collected from a small (1.6 km 2) cultivated catchment in East Devon, UK. Spatial, long term and storm-period nitrate behaviour is described, and attempts are made to model response using a range of statistical techniques for four major gauging stations. These include the main stream and three “representative” subcatchments which reflect variable source areas and include a natural woodland stream, a tile drain and drainage ditch. The variability in partial area contributions from these areas plus the impact of fertiliser application and extreme hydrological conditions are shown to seriously affect the success of modelling procedures.

Tertiary weathering profiles in the plateau deposits of East Devon

A complex of superposed weathering profiles forms the dominant feature of the geology of the East Devon tableland. In the Palaeocene, a lateritic weathering profile, the Combpyne Soil, formed as Chalk deposits underwent dissolution beneath their Tertiary overburden. The profile is well differentiated and polygenetic. The Peak Hill Gravels represent reworked pallid and mottled zones and occur extensively over the tableland. Red earths survive in isolated pockets in the subsequent land surface and traces of laterites occur. In the Sidmouth area. following earth movements in the early Eocene, the Seven Stones Soil was formed. Chemical weathering was less intense than in the older profile. Silcrete formed in both profiles in the Sidmouth area. During the later Tertiary but especially in the Pleistocene these earlier profiles suffered erosion and local redistribution to form the Mutters Moor Gravels. Quaternary soils are developed on fresher Permo-Triassic rocks where the tableland is deeply dissected and are also superposed at various levels of erosion in the older profiles on the plateau surface.

Chemical yields in runoff, and denudation in a small arable catchment, East Devon, England

The calculation of rates of chemical denudation on the basis of streamflow data is subject to a variety of error sources, ranging from the initial sampling and chemical analysis scheme, to the estimation of the non-denudational component of streamflow loss. Most variability in load estimates, based on rating curves, is shown to occur at the monthly level which has serious implications for determining detailed nutrient budgets on this basis. Implications for rates of denudation appear less significant since annual estimates smooth out the high degree of monthly variability. Of great importance in the investigation of process rates is the sampling period length, since a high degree of variability occurs between years which simply reflects variations in the hydrological regime.

Intra‐catchment variability in solute response an east devon example

AbstractModifications to the land use of a small catchment, including clearance, cultivation and an increase in drainage density, are shown to have influenced a number of solute characteristics. Contrasts are drawn between three source areas; an unmodified subcatchment draining an area of mixed deciduous woodland, and a tile drain system and drainage ditch receiving water from cultivated areas. Not only are the modifications identified in terms of mean solute concentrations, but it is also shown that a change in land use alters the interaction between independent hydrological and meteorological variables, and solute response. A tentative explanation is provided for long term solute behaviour in relation to a number of biological geochemical and hydrological controls.

The effects of the 1976 drought and autumn rainfall on stream solute levels

AbstractOperation of a previously existing sampling network during the 1976 drought has provided an opportunity to assess the effects of the drought and subsequent autumn rainfall on the water quality characteristics of a small catchment (9·3 km3) in East Devon. The availability of records for past years has enabled these data to be compared with longer‐term response characteristics.Analysis indicates that the 1976 drought produced a unique solute response, with levels rising markedly during the autumn flush which resulted from the heavy rainfall following the drought period. Concentrations of several ions increased 3–4 times and NO3‐N levels exhibited even greater increases of up to 50‐fold. Some of the factors responsible for these increases and some implications are considered.

Landscape Parks and the Form of Small Towns in Great Britain

The occurrence and significance of landscape parks as elements in British town plans is reported. Parks in which medieval baronial castles form the residence are used to exemplify a four-part sequence of change in parks in the eighteenth and early nineteenth centuries, and the concomitant effects of such change upon adjacent towns. This chronology is then expanded to formulate a general organizational framework applicable to all park-affected towns which, in addition, provides a qualitative measure of comparison between examples. THE landscape park's 'fundamental characteristic of spaciousness was impossible near a town'. So wrote Maurice Beresford in an essay on parks published in 1957;1 yet even the most cursory glance through the plans of the 1:25 000 series of the Ordnance Survey reveals many towns which have one or more landscape parks adjacent to, or even intruding into, their urban fabric. The early nineteenth-century printed maps of Britain provide similar evidence of places where the association of park and town has not continued to the present day. In all, the available cartographic evidence reveals a total of some 400 towns in Great Britain which have, or have had, a park as one element of their town plan. It is the aim of this paper to analyse the effects of one phase of the history of parks on the form of adjacent small towns; namely that period between the 1720os and the early nineteenth century when parks were being re-designed in the landscape mode. DISTRIBUTION AND CHARACTERISTICS In some areas towns with parks form a substantial proportion of the total number of towns in the region. This is most evident amongst the market towns of the Home Counties, but this is not entirely unexpected in view of the known concentration of parks in this region.2 In all, nearly one-third of all towns with adjacent parks are to be found in south-east England. Some towns in this area, Henley-on-Thames, Beaconsfield and Sevenoaks, for example, have as many as three large landscape parks in their immediate environs, as well as numbers of smaller ornamental villa estates. Other areas, most notably East Anglia and Devon and Cornwall, have few examples of such park-affected towns since they were dominated in their land ownership and social structure by the yeomanry and gentry. These smaller landowners, though responsible for some lesser landscape parks in the eighteenth century, generally concentrated their resources upon agrarian improvement before the 1820s.3 In more detail, some interesting groups of similar examples emerge. The small towns of the Tweed drainage basin in Scotland, for instance, each have one or two parks adjoining whose ownership and design chronology compare closely. A second group, distinguished by their owners rather than their location, are those landscape parks created by the successful entrepreneurs of the Industrial Revolution. Such men often built their mansions and planted their parks to overlook the industry and associated urban development which was the basis of their

Geology Explained in South and East Devon

Geology Explained in South and East Devon

Some aspects of the Triassic aquifer in east Devon and west Somerset

Summary The paper reviews the geology of the Triassic in east Devon and west Somerset, presenting new information relating to aquifer thickness and the changes in particle size, which takes place latitudinally. These factors, together with the degree of cementation of the strata, are shown to have a great influence on infiltration, storage and yield. The chemistry of the ground-water is described, and the combined influences of the geology and ground-water chemistry are considered, in relation to the future development of the aquifer.

Factor Analysis of Data from an East Devon Heath: A Comparison of Principal Component and Rotated Solutions

Since the pioneer work of Goodall (1954) and Dagnelie (1960), rather surprisingly little use has been made of factor analysis* by ecologists. As Professor W. T. Williams and others have emphasized, the name 'factor analysis' embraces a group of methods rather than a single technique. A number of biological applications have made use of 'principal component analysis', which, as Seal (1964) says, is 'intended to achieve a parsimonious summarization of a random sample from a . .. universe of multivariate Normal measurements' in contrast to 'factor analysis' which implies a hypothesis that the observed variables can be explained to a definite extent by a smaller number of underlying 'factors'. Lawley & Maxwell (1963) emphasize another, perhaps more practically important, difference-'that whereas a principal component analysis is variance-orientated, a factor analysis is covariance-orientated'. Principal component analysis is concerned primarily with the distribution of the individuals in relation to the axes of greatest variance in the data; factor analysis is concerned with exploring patterns of relationship among the variables. If there are a few strong overriding directions of variation in a set of vegetation data, these are likely to be reflected strongly and in a relatively simple way in a principal component analysis. But if the pattern of variation is at all complex, much interesting and significant ecological information may be as thoroughly hidden among the later and smaller components as it was in the original data. In such cases, the different questions asked by other factor analysis techniques may elicit more informative answers.

Observations on the nature and importance of organic drift in a Devon River

1. Observations on the nature and importance of organic drift in running water were based on a study of the middle course of River Yarty. The latter is an alkaline trout river in east Devon supporting a rich and varied invertebrate fauna. 2. A method for collecting drift is described, and its limitations discussed. 3. From sample analyses, three categories of drift materials were recognized. These were, aquatic organisms derived from the bottom fauna, emerged or emerging imagos produced by the bottom fauna, and organisms from a terrestrial source. 4. It was found that the more abundant species of the bottom fauna were likewise the most abundant in the drift, with the exception of some common benthic organisms which live in more sheltered niches or have a strong means of attachment. However all species occurring in the river were recorded in drift samples at some time. 5. Under normal water conditions drift was added to in habitats with eroding substrata and lost in those with depositing substrata. 6. The emergent and terrestrial categories of drift were present throughout the year but most abundant in spring and summer. The terrestrial category was found to be greater in areas with considerable vegetational overhang. 7. Limited data are presented in support of the function of drift in spreading aquatic organisms over the course of the stream, and the importance of this in restocking habitats denuded by the scouring action of severe spates. 8. From an examination of gut contents and field observations, further evidence for the drift feeding habits of salmonid fish is presented, but not to the complete exclusion of bottom feeding activity. 9. Drift in the middle course of the River Yarty is briefly compared with that in upland streams and it is suggested that the nature and effects of drift may vary considerably within the different courses of a river.

Family limitation in pre-industrial England.

Data on baptisms marriages and burials obtained from the parish registers of Colyton in east Devon England from 1538-1837 were used to identify fertility changes in the parish during that period. The Henry method of family reconstitution was applied to the data. The Colyton register was uninterrupted from 1538-1837 but the degree of detailed information contained in the records varied at different times. These differences were examined from a methodological point of view to determine the amount of information required for applying the family reconstitution method. Analysis of the data revealed that from 1550-1645 the birth rate was high compared to the death rate. From 1645-1730 the birth rate was low in comparison to the death rate and the population of Colyton declined. From 1730-1785 there was a balance between birth and death rates and from 1780-1837 births exceeded deaths. Changes in the mean age at marriage explained some but not all of the fluctuations in the birth rate. A comparison of data for the high marital fertility period of 1560-1629 with data from the low marital fertility period of 1645-1720 revealed evidence that the inhabitants of Colyton were practicing birth control during the later period. Mean birth intervals for the 1st-4th births were 27.5 months for the earlier period and 31.4 months for the later period. There were more childless marriages in the later period thanin the earlier period. From 1645-1720 among women aged 30-34 those who married after the age of 30 had a higher fertility rate than those who married before they were 30 years old. The conclusion was reached that societies worked out different types of equilibriums between population size and resources. Some socieities as posited by Malthus produce they maximum number of people and they minimize the amount of resources available for each individual. Other societies such as the community of Colyton minimize population size and maximize resource allocations to their members.

Dry valleys and the composition of the drainage net

The first two laws of drainage composition are illustrated by analysis of the stream channel net and the valley net, both obtained by field work in the Otter basin in south east Devon, and these results are then compared with those based upon data derived from available 1:25 000 topographic maps. Each of the three groups of data illustrates the two laws. Where dry valleys occur the present stream channel net (approximated, if necessary, by blue lines from maps) should be used for correlation with present hydrological data because the ratio of valley length to stream channel length in the Otter basin and four other areas of Devon is approximately 1.8.

The Bearing of Superficial Deposits on the Age and Origin of the Upland Plain of East Devon, West Dorset and South Somerset

The Bearing of Superficial Deposits on the Age and Origin of the Upland Plain of East Devon, West Dorset and South Somerset

The high platforms of east Devon

The high platforms of east Devon

Mortality amongst Plants

ON the Cretaceous plateau that occupies so much of East Devon (800 ft.–900 ft.) beech trees flourish in considerable numbers. The roads crossing the upland are separated from the adjoining enclosures by massive earth banks that are quite remarkable for their breadth and solidity, some being upwards of twelve feet in breadth and six to eight feet in height. On these banks beech trees usually grow, and in some instances form a continuous avenue. Between the roads and the banks are shallow ditches, and in the late spring the bottoms of these ditches are completely green with the first true leaves of seedling beech. None of these come to maturity, as they are browsed off by rabbits. Even in the enclosed ‘rough lands’ beech seedlings exist in abundance, but only where some protective environment occurs does the seedling achieve maturity. The mortality must be enormous.

From Trackway to Turnpike: An Illustration from East Devon

From Trackway to Turnpike: An Illustration from East Devon