Geology of the Llanidloes area: Acknowledgements and notes

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This page is part of a category of pages providing a summary of the geology of the Llanidloes district (British Geological Survey Sheet 164).
Links to other pages in this category can be found at the foot of the page.

Authors: Wilson, D, Burt, C E, Davies, J R, Hall, M, Jones, N S, Leslie, A B, Lusty, P A J, Wilby, P R, and Aspden, J A.


This Sheet Explanation was written and compiled by D Wilson, based on contributions by co-surveyors, and edited by J E Thomas and J R Davies. The figures were drafted by H W Holbrook. The district was largely surveyed during 2006 by J A Aspden, C E Burt, J R Davies, M Hall, N S Jones, A B Leslie, T H Sheppard, P R Wilby and D Wilson as part of the Geocymru Project, supported by a grant from the Welsh Assembly Government. The southern and eastern margins were mostly surveyed by R Cave, J R Davies, C J N Fletcher, A J Reedman and R A Waters during the mapping of the adjacent Montgomery and Rhayader districts between 1986 and 1989; areas along the western margin were surveyed by R Cave between 1965 and 1972 as overlap from the Aberystwyth district. Biostratigraphical determinations of Silurian rocks were provided by A Snelling and J A Zalasiewicz (Leicester University). P A J Lusty contributed to the section on mineral resources. The British Geological Survey gratefully acknowledges the co-operation of landowners and farmers in allowing access to their lands during the geological survey.


The word ‘district’ refers to the area of the geological 1:50 000 Series Sheet 164 (Llanidloes). National Grid References (NGR) are given in square brackets. The district lies within NGR 100 km squares SN and SO; grid references are prefixed by these letters. Symbols in round brackets after lithostratigraphical names are the same as those used on the geological map.

The grid, where it is used on figures, is the National Grid taken from Ordnance Survey mapping.

Geology of the Llanidloes area — contents[edit]