ANNIVERSARY ADDRESS OF THE PRESIDENT. T45 



tte Calciferoiis Sandstones, many hundred feet above the position of 

 the top of the plateau-lavas. 



So great an amount of material has been here removed by denu- 

 dation that not only has the volcanic zone been bared away, but 

 the vents which supplied its materials have been revealed in the 

 most remarkable manner over an area some twenty miles long and 

 eight miles broad. Upwards of forty necks of agglomerate may be 

 seen in this district, rising through the Silurian, Old Red Sandstone, 

 and lowest Carboniferous rocks. It fills the geologist with wonder 

 to meet with those stumps of old volcanoes far to the west among 

 the Silurian lowlands, sometimes fully ten miles away from the 

 nearest relic of the bedded lavas connected with them.^ That these 

 vents, though they rose through ground which at the time of their 

 activity was covered with the volcanic series of the plateaux, do not 

 belong to that series, but are of younger date, has been proved in 

 several cases by Mr. Peach. He has found that among the blocks 

 composing their agglomerates, pieces of the sandstones, fossiliferous 

 limestones, and shales of the Cement-stone Group, overlying the 

 plateau-lavas, are to be recognized. These vents were therefore 

 drilled through some part at least of the Calciferous Sandstones, 

 which are thus shown to have extended across the tract dotted with 

 vents. After the volcanic activity ceased, fragments of these strata 

 tumbled down from the sides into the funnels. Denudation has 

 since stripped off the Calciferous Sandstones, but the pieces detached 

 from them and sealed up at a lower level in the agglomerates still 

 remain. Mr. Peach's observations indicate to how considerable 

 an extent sagging of the walls of these orifices took place, with the 

 precipitation not merely of blocks, but of enormous masses of rock, 

 into the volcanic chimneys. In one instance, between Tudhope 

 Hill and Anton Heights, a long neck, or perhaps group of necks, 

 which crosses the watershed, shows a mass of the red sandstone, 

 many acres in extent, and large enough to be inserted on the 

 one-inch map, which has fallen into the vent. 



From the descriptions published more than thirty years ago by 

 Jukes and his colleagues in the Geological Survey of Ireland, 

 geologists learnt how full and interesting are the proofs of great 

 volcanic activity contemporaneously wuth the deposition of the 

 Carboniferous Limestone series in the Limerick district of the South- 



^ They have been recognized and mapped by Mr. B. N. Peach for the Geo- 

 logical Survey. See Sheets 11 and 17, Geol. Surv. Scotland. 



