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| 15 Apr 2008 08:31:52 am |
 Geological Survey of Ireland Maps 6 inch |
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Category : archeology
| Posted By : anna |  Comments[79] |  Trackbacks [0] |
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| 15 Apr 2008 08:26:13 am |
| Geological Survey of Ireland Maps 6 inch |
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Category : archeology
| Posted By : anna | Comments[93] | Trackbacks [0] |
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| 31 Mar 2008 09:05:11 am |
| Memoirs |
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Category : General
| Posted By : anna | Comments[55] | Trackbacks [0] |
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| 31 Mar 2008 08:58:32 am |
| Geological Survey Mapping in Ireland. |
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Geological Survey Mapping in Ireland.
The Ordinance Survey’s coverage of Ireland on the scale of one inch to one statute mile ( 1:63,360) was planned during the Napoleonic wars to form part of a single military map of the United Kingdom. By the time the Irish branch was set up in 1824, the priority was no longer military and county maps were drawn up at the larger scale of six inches to a mile. Only when the last of these large scale maps were completed in 1846 did work commence on the drawing and engraving of the of the Irish one inch map.
In terms of Geological mapping, Ireland nurtured some notable pioneers of geological cartography and produced an official geological survey some ten years before the establishment of a similar survey in England. It was to Ireland that British geologists came to learn the art of six -inch field mapping. The maps of Leitrim gathered here courtesy of the Geological Survey of Ireland ( copyright free) are both the six inch field maps drawn by geological teams during the 1840’s /50’s and the later one inch maps published in 1878.
The one inch maps depict hill shading as closely spaced fine lines known as hachures, the engraving of hachures was a slow and difficult process, in later editions the hachures were lightened by printing them in brown and in the black and white versions of the early twentieth century were replaced by contour lines.
Of the six inch maps the geological field notes are drawn or painted on watercolour directly onto ordinance survey maps and include direct observations; Leitrim map 12.3; near Ballaghnabehy Lough, ‘ a very fine quarry of flaggy white quartzite grits and sandstone flags can be raised here to almost any size. They are much used in Sligo and Enniskillen for paving streets. It is a much softer rock than the same grits on the Glenfarne Mountain, the latter being so hard as to turn the workmans tools’. Another exampleLeitrim 12.4 Ardvarney. ‘ massive white quartzite grits and fine conglomerates, ice moulded? Direction of movement running E to W.’
Memoirs to the 1’’ maps.
To accompany the 1878 1’’ geological maps of Ireland, the Geological Survey of Ireland produced explanatory memoirs to give a detailed breakdown of the topography of the areas covered on each map sheet. For example the principal places described in the memoir for sheets 66 & 67 are Ballymote in Co Sligo, Ballyfarnon in Roscommon, Drumshambo, Ballinamore and a small part of Carrick on Shannon in Leitrim.
In the forward by the Director General of the survey, Andrew C Ramsey notes that…
‘there is exhibited a very interesting and complete series of all the Carboniferous Strata of Ireland, from the sandstones that underlie the Lower Sandstone, up to an including the Lower Coal-measures. The Old Red Sandstone also forms a long tract of country; and, indeed, on either side of Lough Allen, and near its southern end, the Geologist may examine all the formations of the district from the Lower Silurian up to the outlier of the Coal measures that crown Slieve-an-Ierin, 1,922 feet above the sea. It is a rare thing in most countries to find so much comprised in so small a space.’
There follows 37 pages of minute detail of the findings of the survey teams. The contents cover: physical geography, geological formations, palaeontological notes ( including a description of what fossils were discovered in which townland and where, eg:
Liscreaghan, at railway cutting, three quarters of a mile west of Woodbrook, three miles and a quarter west of Carrick on Shannon: Lower Limestone. Actinozoa;Corals, Lithodendron affinis; Junceum; Mullusca; Polyzoa, Feirestella membranacea; Brachiopoda; Terebratula hastate.)
Accounts of mines, minerals and principal faults, this section includes accounts of landowners and their various attempts to sink shafts and capitalize on the coal seams on their land sometimes the author permits himself the odd wry remark:
‘ I may here remark that Hugh O’Berine, esq., of Jamestown House spent several thousand pounds in sinking a shaft in seach of coals about half a mile east of Lough Allen, through the base of the Yoredale beds into the upper limestones. It seems that he acted on the advice of some practical men, which only shows how capital can be wasted when its outlay is not directed by a knowledge of the simplest principles of geology’. |
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Category : General
| Posted By : anna | Comments[53] | Trackbacks [0] |
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| 31 Mar 2008 08:51:12 am |
| Maps |
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Category : General
| Posted By : anna | Comments[57] | Trackbacks [0] |
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| 31 Mar 2008 08:42:59 am |
| Environmental Quarterly |
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Issue No, 44 , Environmental Quarterly of Sherkin Island Marine Station, 2007
This issue of the magazine has some interesting articles pertinent to some of our research interests;
Prof. Barrie Dale in Looking Back into the Future of Climate Change talks about the hysteria surrounding the debate on climate change and advocates a more informed approach by politicians and the media. Dr John Akeroyd, botanist writes about the threat to Irelands precious wetland flowers from pollution and invasion by alien species and Dr Sarah Varian outlines the new marine environmental outreach project seeking input from the Irish beach going public to report sightings of Mermaids Purses in a national survey of shark, Skate and Ray breading grounds.
For more information check out www.sherkinmarine.ie.
Dr Sarah Varian, Zoologist. Marine dimensions. www.marinedimensions.ie.
Dr John Akeroyd, editor of ‘The Wild Plants of Sherkin, Cape Clear and adjacent islands of West Cork’ 1996.
Prof. Barrie Dale, Dept. of Geosciences, University of Oslo, Blindern, Oslo Norway.
I have a couple of copies if anyone is interested. Cheers Anna. |
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Category : General
| Posted By : anna | Comments[51] | Trackbacks [0] |
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