E. T. Hardman — Fosdliferous Pliocene Clays. 557 



marked cleavage. The basalt on which they repose was evidently 

 the ancient shore of the lake. It is greatly water-worn, and the 

 pebbly clays lying on it and in the hollows are clearly shore-beds. 

 A little higher up the stream the basalt rises abruptly into what 

 must have been a bold shore cliff. A deposit of drift disguises the 

 surface appearance of this, but in section it is very distinct. Some 

 distance south of this, on the Grienavy Eiver, the basalt presents an 

 exactly similar aspect. The old cliff is very well shown, while a 

 little lower down the Pliocene clays, full of plants and lignite, are 

 found; but the junction is hidden. 



The presence of these ancient cliffs not only serves to mark the 

 former extent of the lake — which must have been at least double its 

 present dimensions — but also shows that glaciation could not have 

 acted very energetically in that district, since in that event it would 

 have undoubtedly removed all traces of them. 



A similar shore and cliff may be seen on the northern margin of 

 Lough Neagh, just under Shane's Castle, Antrim (PL XXII. Fig. 2). 

 But the clays do not extend so far north as this, and the basalt is laid 

 bare on the shore, presenting rather a remarkable appearance in some 

 places, and rounded as if by ice. Another old cliff occurs along the 

 south side of the point jutting out by Langford Lodge. Both of 

 these are, however, more recent than the drift. 



The Lough Neagh Clays had hitherto proved barren of any fauna. 

 I had examined carefully every excavation that had been made in 

 the potter's clay on the south side, without success ; nothing but 

 plants being obtainable. The Rev. Dr. O'Meara, whose valuable 

 researches on Irish Diatomaceee are so well known, thought it likely 

 that these clays might yield Diatoms, and I procured some specimens 

 for him at Professor Hull's request. These, I understand, gave no 

 result ; and it appeared certain, therefore, that no fossils, save land- 

 plants, were to be expected from these strata. It was, then, with 

 much satisfaction, that while examining the section detailed above, I 

 came on a bed of clay full of shells. 



The fossils are mostly confined to a band about a foot thick, and 

 are very abundant. They appear all to belong to a species of TJnio. 

 Owing, however, to their extremely delicate structure, and the soft 

 and friable nature of the deposit in which they lie, it was very 

 difficult to obtain good specimens, and unfortunately those which I 

 brought away with me received such damage during their transit 

 that it was almost useless to attempt to determine them. Mr. W. 

 H. Baily, F.G.S., to whom I submitted them, is inclined to think 

 that they may possibly belong to a new species. They are not 

 unlike the Unio Solandri (?) of the Upper Eocene of Hordwell Cliff, 

 Hampshire, so far as external appearance goes. In PL XXII. Fig. 3 

 there is a representation of two of the shells, the originals are greatly 

 crushed and dilapidated.^ (a) will perhaps serve to give some idea 



^ Having been favoured by Mr. Hardman with an opportunity to examine the 

 specimens in question, we have been led to the opinion that the lines of strire indicate 

 rather a Mytilus or Modiola-Vike shell, than a Unio ; but the shells are too fragment- 

 ary to enable one to speak with certainty even as to the genus. — Edit. Geol. Mag. 



