500 Prof. Cole & T. Hallissy—The Wexford Gravels. 



near Dublin in his ' interglacial series ', a position which lie lias since 

 consistently maintained. He emphasized the existence of an Upper 

 and Lower Boulder-clay at Killiney, a matter that has since been 

 questioned. The Irish gravels were naturally at that time held to 

 have been deposited in the sea during a temporary depression of tlie 

 land ; but Hull holds strongly that their occurrence indicates a milder 

 climate,^ after which a partial return of a cold climate produced local 

 glaciers and icebergs. As regards Wexford, he indicates the super- 

 position of an Upper Boulder-clay on the ' manure gravels ', while 

 apparently remaining unaware of the existence of the glacial ' marl ' 

 below the gravels. 



G- H. Kinahan,^ whose opposition to Hull's views must often be 

 regarded as a matter of principle, promptly recorded his opinion that 

 the Irish gravels lay on no definite horizon. James Geikie,^ on the 

 other hand, accepted Hull's opinion as to their interglacial character. 



Kinahan, in order to emphasize his belief that the glacial series in 

 Ireland was continuous, referred the gravels to the melting of the ice, 

 and the boulder-clay above them to the downwashing and re-arrange- 

 ment of the earlier glacial accumulations and other material on hill 

 slopes. The Upper Boulder-clay was for him merely ' glacialoid ' "^ ; 

 and in 1884 (see reference later) he remarked that many of the sands 

 and gravels are probably younger than the material now lying over 

 them. In 1876^ he again urged that the deposit above the shelly or 

 ' manure ' sand of Wexford was not directly originated by ice. About 

 this time he was engaged on the geological survey of Co. Wexford, 

 and he records the succession of deposits far more clearly than any of 

 his predecessors.^ He relies especially on the coast-sections near 

 Kilmore in the south of the county, and points out the existence of 

 a green sand at the base. Near St. Patrick's Bridge (p. 44) he gives 

 the upward succession as ' marl ', ' gravel ', and a ' glacialoid drift ' ; 

 but elsewhere he often records the interlocking of gravel with his 

 glacialoid drift. The green sand, as we shall see later, is not 

 glauconitic, but is a chloritic derivative from the underlying Palaeozoic 

 rocks. In a subsequent memoir published in 1882' he mentions 

 a thick mass of 'glacialoid' drift as underlying 'manure sand' at 

 Ballynaclash, half a mile south-west of the mouth of the Blackwater. 

 We may say at once that we regard Kinahan's efi"orts to distinguish 

 a 'glacialoid' drift from boulder-clay as entirely academic, and that 



^ " Observations on the general relations of the Drift Deposits of Ireland to 

 those of Great Britain " : Geol. Mag., 1871, p. 299. 



^ " Middle Gravels (?), Ireland " : Geol. Mag., 1872, p. 267. 



^ " On Changes of Climate during the Glacial Epoch " : Geol. Mag., 1872, 

 p. 105. 



^ "Glacialoid or re-arranged Glacial Drift": Geol. Mag., 1874, p. 111. 

 On p. 113 Kinahan states that his glacialoid drift occurs above and also 

 interstratified with the Wexford gravels. On p. 172 he allows that local ice 

 may have formed a true drift over gravels in limited areas of Ireland ; but he 

 opposes the idea of two separate glaciations. 



* "Irish Drift. Sub-groups — Aqueous and Glacial Drifts": Journ. Eoy. 

 Geol. Soc. Ireland, vol. iv, p. 217. 



" Geol. Surv. Ireland, Mem. to Sheets 169, 170, 180, 181, 1879, pp. 12-14, 

 28-51. 



' Mem. to Sheets 158 and 159, p. 34. 



