82 



BRITISH EOCENE ELORA. 



in total thickness, though it is not apparent that their base is exposed. The quarry runs 

 east and west for nearly 200 yards, the direction having been determined by a dyke 

 which forms for some distance its northern face. Plants occur throughout the finer 

 kinds of sediment, though fir-cones sometimes extend to the coarser matrices and are 

 generally more abundant towards the base. They have hitherto been supposed to be 

 lacustrine, but the coarseness and brecciated nature of some of the layers and their irre- 

 gular bedding seem to indicate, on the contrary, deposition by running and shifting water 

 of very variable volume. The presence of fir-cones and other fruits, associated together 

 with objects, such as Pine-needles and leaves, of such very differing specific gravities, 

 does not, on the other hand, accord with what is usually observed in assemblages of plant 

 remains deposited by moving water. Perhaps the true explanation must be sought in a 

 series of backwaters or isolated pools of sluggish or stagnant water liable to sudden floods 

 or great accessions of volume. They are certainly neither lacustrine nor swamp deposits. 



There is still considerable doubt as to the true matrix of the celebrated silicified wood 

 of Lough Neagh, but this is a question with which we are not here materially concerned. 

 The iron-stones with leaf-impressions, which are found on the shores of the same lough, 

 are of more immediate interest, and it would be of some importance to ascertain their real 

 age. I believe them to be in situ in the extensive so-called Pliocene deposits of blue clays 

 and surturbrands, which are stated to occupy an area ten miles in length by four miles in 

 breadth, and to have been bored to a depth of 300 feet without bottom.^ The leaves 

 seem to differ from those of the other localities, and to be nearer those of existing Beeches, 

 Alders, and Willows. The nodules appear in every way identical with those met with 

 on the Norfolk coast near Bacton at certain states of the tide. On the other hand, the 

 resemblance they bear to nodules brought by Mr. Whymper from Greenland, of much 

 older dates, is no less remarkable. The supposed Pliocene deposits seem to be younger 

 than the period of volcanic activity, as they are quite free from scoriae and ash, and 

 independent of the Basalts. Their true age, however, is an interesting problem which 

 the plant remains will undoubtedly enable us to solve. 



CuPRESsus^ Pritchardi, Goepp., sp. Plate XVI, figs. 8 and 9; Plate XVIII, fig. 1, 



cones only ; Plate XIX. 



PiNiTES Pritchabdi, Goeppert. Toss. Conif., p. 220, 1850. 



CUPRESSITES MacHenrii, Bailj/. Quart. Journ. Geol. Soc, vol. xxv, p. 357, pi. xv,. 



fig. 5, 1869. 



CuPKESsoxYLON Pritchardi, Krauss in Schimper. Pal. Veg., vol. ii, p. 376, 1870-72. 

 Basaltic formation, Ballypalady, County Antrim. 



The leaves are very small and scale-like, oval-pointed, imbricated in four rows, either 

 1 ' Brit. Assoc. Report.,' 1853, Griffith, p. 43. ^ See ante, p. 25. 



