502 Prof. Cole & T. Hallissy—Th'e Wexford Gravels. 



signs of glaciation". He gives a list of eleven Pliocene and sixteen 

 boreal species out of the total of about one hundred moUuscan species 

 recorded, and urges (p. 633) that the facies of the fauna of the marls 

 of Eosslare Bay and "Wexford Harbour is entirely different. He 

 states that these marls overlap the sands and are of much later date. 

 Bell's stratigraphical observations must be read with some reserve. 

 His phrase " illusory drift ", however, may be taken as a develop- 

 ment of Kinahan's ideas. 



As the result of a visit to the district for the examination of the 

 soils of Co. Wexford, the present writers were much struck with the 

 confusion still surrounding the stratigraphy of the local drifts. 

 T. Hallissyi published a general statement in 1912, and a more 

 detailed account of the succession now follows. 



II. The Characters and SaccESsioisr of the Wexford Drifts. 



T. Hallissy has already stated our view {op. cit., p. 178) that the 

 'marl* of Wexford represents "the englacial moraine of the Irish 

 Sea ice-sheet which invaded this portion of the Wexford area from 

 the north-east". This 'marl' is a chocolate-brown boulder-clay, 

 effervescing on the application of hydrochloric acid. The well-known 

 shelly gravels undoubtedly overlie it, and the loam (Kinahan's 

 'glacialoid' type and Bell's "illusory drift") that often occurs 

 above these contains numerous striated stones and is identical with 

 Hull's Upper Boulder-clay. 



The deposits are widely distributed in the country to the east of 

 the Leinster Chain, but are best developed in the south-east of 

 Wexford, where they attain a maximum thickness of about 60 feet 

 on the coast near Grreenore Point ; then, thinning towards the west, 

 they occupy a considerable area of the county below the 300 ft. 

 contour-line. As the chocolate clay is a highly calcareous deposit, 

 possessing on an average about 11 per cent of carbonate of lime, it 

 was formerly extensively used as a manure (see ante). The shell- 

 bearing gravels likewise are said to have been added to the land with 

 the same object,- though there is little traditional evidence to show 

 that this has been the case. At any i-ate, their use for manurial 

 purposes could not have been very general, as no pits that could have 

 supplied a large quantity of material remain in evidence. Both the 

 chocolate clay and the sands and gravels contain numerous arctic and 

 other shells, occurring mostly in a fragmentary condition, and from 

 the latter deposit some distinctly Pliocene forms liave been obtained. 

 In addition, these deposits contain anthracite and bituminous coal, 

 lignite, chalk-flint, jasper, diorite, felsite, red granite, etc. Many 

 striated limestone and sandstone boulders have been found in the 

 chocolate clay, and magnetic iron sand has been obtained from the 

 sands and gravels. The occurrence of the sands and gravels is 

 sporadic, being confined to certain localities situated at intervals over 

 the area, while the ' marl ' and non-calcareous loam form piactically 

 continuous sheets. 



■' " On the Superficial Deposits of the County of Wexford " : Irish Naturalist, 

 1912, p. 175. 

 2 E. Griffith, " Address " : Journ. Geol. Soc. Dublin, vol. i, p. 151, 1837. 



