Geological Relations of the East of Ireland. 281 
The Sutton limestone is connected with that of Howth, St. Doo- 
lagh’s, Feltrim, and Cloghran ; and these exhibit more or less of 
the same organic remains. But one of the most remarkable petri- 
factions, that has occurred to me in the floetz limestone, was found 
at Sutton. It appears to be of vegetable origin, and it bears some 
resemblance to Fig. 1. Plate 25. of Martin’s Petrif. Derbien., which 
is an impression on the sandstone of the Derbyshire coal tract. I 
have analogous impressions also on the roof shale of the Kilienaule 
coal district ; but the Sutton petrifaction is not compressed. The 
portion displayed is part of a stem, nine inches long, one broad, and 
three quarters of an inch deep, consisting in the interior of dark 
grey carbonate of lime, the surface of which is marked with close 
equal longitudinal striae, with some appearance of joints ; but these 
are not distinct, from the fractured state of the stone. Some bota- 
nical friends, to whom I exhibited this specimen, consider it to be 
an equisetum. I have not met with any similar specimen in any 
other part of the limestone tract. 
§ 181. The limestone field has afforded indications of metals in 
many parts of its extent ; principally of lead and copper. Dissemi- 
nated iron pyrites, copper pyrites, blende, and galena may casually 
be observed in the limestone ; but veins also have been found, which 
have yielded considerable quantities of galena, so far as they were 
wrought; the veinstone being commonly calcareous spar, some- 
times accompanied by brownspar, and more rarely by fluor spar. 
The floetz limestone of Ireland is, however, in general, singularly ill 
calculated for the conduct of mining operations, the position of that of 
England and Wales being much more favourable. In Ireland, this 
formation occupies the lowest and richest part of the country, and 
frequently supports a considerable depth of alluvial matter and soil. 
Hence mines cannot be freed from water without machinery, and 
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