192 Proceedings of the ttoi/al Irish Acadcmi/. 



The rock in whiuli tliese fossils occur is an onliiiaiy dark, almost black, 

 Carboniferous shale. Tlie surface of I lie slialc is traversed by a grain or 

 structure resembling cleavage, but probably merely due to the direction of 

 fracture. The efiect of this on the visibility of the fossils was very serious, 

 but the dilliculty was to a considerable extent overcome by mounting them 

 in Canada balsam and covering with a ^hiss slip. This procedure also 

 liad the advantage of preventing tlie decomposition of the pyrites, in 

 which the fossils appear to be preserved. The usual dilUculties of opaque 

 illumination were experienced, but the best results were ultimately obtained 

 by condensing the light from a single electric bulb along (he grain of tlie 

 rock. In i)reparing the plates and te.xt-figures all the outlines, and as far as 

 possible the details, were I'Ut in with the camera lucida, the sketches being 

 completed fiueliand. 



II.— STltATlUllAl'HICAL POSITION OK THE FOSSILS. 



The folliiwing details as to the stratigraphy of the beds in which these 

 Estherian fossils were found have been kindly supj)lied to me by theollicers tif 

 the Geological Survey of Ireland : — 



The fossils came from a deptli of 830 feet in a boring put down by 

 Mr. IJ. H. I'rior Wandesforde at Ardra, a mile and a half N. 30° E. from the 

 cross-roads in Casllecomer. Tiiey were eolleeled by the Geulogiwil Survey, 

 tlie oRicers of wiiicli, through the courtesy of Mr. Wandesforde, had access 

 to the cents of all tlic borings put down by liim in search of coal in this 

 district. Tlie beds in which they occur lie some live and a half fathoms bchiw 

 the position of the Skehana coal-seam, on or just above a well-detined 

 slraligrapliical horizon, which has been recognized in many parts of the 

 Kilkenny coallieUl. This horizon has been called the " lleck-rock " by the 

 geologists working in the Held— a name which fairly well describes its nature. 

 1 1 was recognized by Mr.Wandesforde atan early stage of the boring (jperations 

 OS (Kisscssing distinctive characters, and he drew the attention of the 

 Geological Survey t<j it when they came to work on the field. It is a dark- 

 coloured massive rock of remarkable tougliness, having innumerable small 

 Hecks of slightly darker colour along the very obscure bedding jilaiies. It 

 generally yields badly preserved gouiatites and otiier marine fossils, and 

 where normally develoiicd to the south and east of Castlecomer is obviously 

 of marine origin, while the shales immediately alx)ve generally yield a very 

 considerable marine fauna The origin of the flecked structure is, however, 

 quite unknown. As far as can be ascertained this is the normal condition 

 of things as i-egards this horizon over the greater part of the coalfield, but in 

 the Skehana district to the north-west of Castlecomer very marked lateral 



