176 The Irish Naturalist. September, 



pebbles of chalk-flints and jasper, and lumps of anthracite, 

 lignite, and bituminous coal. To this deposit the name 

 " manure gravel " has been applied, since, hke the " marl," 

 it has been found to possess a considerable fertilising value. 

 The manure gravels do not occur in a continuous sheet, but 

 in isolated patches often far removed from one another. 

 Finally, overlying the marl and gravel, and extending 

 throughout the whole area, a third deposit consisting of local 

 more or less angular rock-fragments in a loamy non-cal- 

 careous matrix has been recognised. This constitutes the 

 " glacialoid " drift of Kinahan and the "illusory or fic- 

 titious " drift of Bell. 



As early as 1846 the shelly " marl " and gravels of Wex- 

 ford attracted the attention of geologists. About that date. 

 Captain James and Professor Edward Forbes^ examined the 

 deposits and found in them, amongst others, fossils such as 

 Fusus contrarius, &c., of a distinctly Pliocene facies. The 

 finding of such a fauna in the series led these observers to 

 refer the formation to the Pliocene System. 



Later, G. H. Kinahan, when surveying the district, 

 observed that the " marls " rested on a glaciated rock-floor, 

 and he was thus forced to recognise the more modern 

 character of the formation. -^ To account for the uniformity 

 and marine aspect of the deposit, he postulated a post-glacial 

 submergence of the land to the 300-foot contour line, and in 

 this post-glacial sea — the " Esker Sea " — he supposed the 

 marl and gravels to have accumulated. Kinahan rightly 

 described the gravels as resting on the marl, with material 

 composed of local rubble augmented by detritus from the 

 hills overlying these deposits. From the year 1887 to 

 1890, Mr. Alfred Bell presented to the British Association 

 a series of reports on the manure'gravels of Wexford, in which 

 he gives an exhaustive list of the shells found in this forma- 

 tion. The list includes many molluscan forms not at present 

 living in the adjoining seas, and amongst them, a Pliocene 

 facies which he considered not earlier than the late Pliocene 



1 Journ. Geol. Soc. Dublin, vol. iii,, p. 195. 



■^ See Mems. Geol. Survey of Ireland to sheets 158 and 159 (1882), and 

 169, 170, &c. (1879). 



