lowest member of the trap deposit, which is usually a bed of ochreous bole: the flints so imbedded have usually themselves acquired a red tinge, apparently by percolation, from the oxidated iron of the stratum in which they lie. This aggregation of flints, bedded in red ochreous bole, forms at Macgilligan, a stratum thirteen feet thick. It may be observed, also, near Lame and near Belfast, and seems indeed of almost universal occurrence.
List of organic remains found in the chalk of Ireland.
| genera. | species.. | places. |
| Echinus | cidaris mamillata | Kenbaan Antrim; Slievgallion Derry. |
| scutatus | Pollen quarry near Agenloo Deny. | |
| Terebratula | vulgaris | Ballyness Derry. |
| sulcata | Ibid. | |
| Pecten | earless | Ballycreem Derry. |
The foregoing specimens closely agree with the fossils of the English chalk.
Belemnites are common in most of the quarries opened on this bed in Ireland: many of the bodies in the English chalk, once supposed to be belemnites, are now regarded as the pallisadoe spines of the echinus. Some few, however, are undoubted belemnites; the Irish specimens appear to be generally true belemnites.
Specimens of cornua ammonis, from five inches to one in diameter, occur in the Pollen quarry; but not having myself examined these, I cannot say how far they agree with some of the very few varieties which are found in the lower strata of chalk in England. The flinty nodules often contain fossils similar to those of the surrounding chalk, and present, in addition to these, traces of alcyonia.
