Multi-Method Remote Sensing Survey at Lough Croan, Co
Total Page:16
File Type:pdf, Size:1020Kb
2018 MULTI-METHOD REMOTE SENSING SURVEY AT LOUGH CROAN, CO. ROSCOMMON – RCC HERITAGE RESEARCH BURSARY 2018 Project Report DANIEL CURLEY, 31ST OCTOBER 2018 Table of Contents Table of Figures ............................................................................................................................ 2 Introduction ................................................................................................................................. 3 Lough Croan – Physical Description................................................................................................ 4 Placename Evidence ..................................................................................................................... 4 Communication routes ................................................................................................................. 7 Historical background ................................................................................................................... 8 Artefactual assemblages from Lough Croan.................................................................................. 10 Focussed archaeological research at Lough Croan ........................................................................ 12 Discussion of the Preliminary Results of the Remote Sensing Investigations ................................... 19 Future Work ............................................................................................................................... 22 Acknowledgements .................................................................................................................... 23 Bibliography ............................................................................................................................... 24 1 Table of Figures Figure 1 - Contoured topographical plan of Lough Croan, indicating recorded archaeological monuments, and principal placenames. (LiDAR data courtesy of OSi) .............................................. 7 Figure 2 - Digital modelling of the water level of Lough Croan turlough to 69m OD. Note the range of 'islands' located on the lake, particularly the collection of landmarks at the centre of the lake. The red arrow indicates the location targeted for remote sensing investigation. (Data courtesy of OSi, image generated by LGS) ............................................................................................................ 12 Figure 3 - Location of area chosen for investigation, outlined in red on a six-inch OSi map with plotted location of RMP RO044-089--- to the west. (Map OSi/ASI) ................................................. 13 Figure 4 - LiDAR image of the survey area, marked by a rectangle (LiDAR data courtesy of OSi, acquired courtesy of RIA); Figure 5 - Location of area considered for investigation, with mound outlined in red on an aerial photograph, with plotted location of RMP RO044-089--- to the west. (Photo: Digital Globe).................................................................................................................. 14 Figure 6 - Contoured topographical plan of the target location, derived from LiDAR data (Data courtesy of OSi, image generated by LGS) .................................................................................... 14 Figure 7 - Earth Resistance Survey in progress at Lough Croan, with Total Station in foreground. (Image courtesy of Kevin Barton) ................................................................................................. 15 Figure 8 - Reconnaissance survey geo-referencing the groundfast stones on the summit of the promontory at Lough Croan, set within the survey grids. (LiDAR data courtesy of OSi, image generated by LGS) ...................................................................................................................... 16 Figure 9 - Electrical Resistivity Tomography (ERT) survey conducted over the summit of the promontory at Lough Croan. (Image courtesy of LGS) ................................................................... 17 Figure 10 - Earth Resistance Survey conducted in 10m x 10m grids. (Image courtesy of LGS) ........... 18 Figure 11 - Magnetic Susceptibility Survey conducted in 10m x 10m grids. (Image courtesy of LGS) . 19 2 Introduction This report is being submitted to the Heritage Office, towards the partial fulfilment of the conditions of my grant of a County Roscommon Heritage Research Bursary for 2018. The report begins with a detailed historical background for the Lough Croan landscape, which provides justification for the targeting of Lough Croan for the application of the multi-method remote sensing survey in the landscape. This is followed up by a consideration of the recently acquired LiDAR dataset of a substantial area of the Lough Croan landscape, which the author received thanks to a Royal Irish Academy grant award. This LiDAR dataset has enabled the author to produce a Digital Terrain Model (DTM) of the Lough Croan landscape, which has provided a detailed topographical basemap from which to study the archaeological monuments at Lough Croan. This has uncovered a number of anomalies which may prove to be unrecorded monuments, while also enabling the author to digitally ‘flood’ the turlough at Lough Croan, in order to better understand the archaeological remains within the former lake, as well as its near vicinity. This data has been vital in terms of identifying a specific monument for multi-method remote sensing survey, and provided the evidence required to target the monument that was studied thanks to the funds of the research bursary. The survey will then be discussed, and some preliminary results and discussion will be communicated. These results have not been fully processed to date, therefore the conclusions provided in this report may not be the conclusions arrived at upon the final submission of the PhD research. As mentioned, this research is part of this author’s PhD research, which is being carried out in NUI Galway, and is based on an exploration of the archaeology of the Úa Cellaig (O’Kelly) lordship of Uí Maine, c. 1100-1600. The research focusses on the understudied later medieval O'Kelly subkingdom and later lordship of Uí Maine. At its height in the fifteenth century, this lordship consisted of large parts of east Galway and south Roscommon. The principal aim of the research, taking a multi- disciplinary approach using the available archaeological, remote sensing, historical and literary evidence, is really to chart and trace the formation, character, physical appearance and development of Uí Maine from the twelfth century through to the demise of the O’Kelly lordship in the late sixteenth and early seventeenth centuries. There are two key aims of the author’s research which the bursary will aid substantially in achieving. One is to try and identify and investigate the evolution of the settlement archaeology of the O’Kelly lordship through time - from ringfort, crannóg and cashel, to towerhouse castle and other fortified residences of the late medieval/early modern period. The second is to identify the cenn áiteanna or lordship centres of the O’Kelly kings and lords of Uí Maine in the high and late medieval period. A wealth of hitherto-untapped archaeological (including unpublished and partially published excavation reports linked to infrastructural projects), historical and literary sources exists for Uí Maine and its adjacent areas. The available rich cartographic evidence (such as the Strafford map of the 1630s), combined with much of the data from the latter sources, would suggest that the landscape of later medieval Uí Maine can be reconstructed. The available source material will then be supplemented by desk and fieldwork-based methodologies, in order to develop as complete a picture of later medieval Uí Maine as possible, which will then offer a range of opportunities for development in the area. This author intends on using the research as a key initiator in the development of rural tourism initiatives in the south Roscommon/east Galway region, one that has been identified as deficient in terms of harnessing its tourism potential. Through my experience of working in a similar area of high 3 rural tourism potential, I can identify outputs that can serve as templates for similar projects in the research area, with themes including but not exclusive to archaeological, historical and heritage tourism, outdoor and walking tourism and genealogy. Lough Croan – Physical Description The turlough of Lough Croan has an approximate area of 106.9ha (Goodwillie, 1992, p. 148), of which 106.2 ha lies within the boundary of the Lough Croan Turlough Special Area of Conservation (SAC). The turlough measures approximately 3.4 km at its furthest extents, and 570 m at its widest point. The elevation in the basin of the turlough is approximately 67.5 m OD, while the elevation of the surrounding glacial hills approaches 104 m to the south and 106 m to the north of the turlough, located in the townlands of Cronin and Correal respectively. The underlying geology of the Lough Croan area, and indeed Co. Roscommon as a whole, is primarily one of Carboniferous Limestones (Parkes, Meehan, & Préteseille, October 2012, p. 18), while the soil composition of the turlough bed is primarily peaty, with silt and an impure marl in places (Goodwillie, 1992, p. 149). The chemical composition of soils in most of these limestone regions contains an abundance in soil nutrients which are very complementary to high-quality cattle