108 Scientific Proceedings, Royal Dublin Society. 
What time did the animal live? (When I refer to time, it is 
almost unnecessary to say that I refer to geological time, whose 
periods are marked by various formations and deposits.) 
Among the latter a very marked one is the Lower Boulder clay, 
which is spread over a large portion of northern Europe and 
America, and is said to cover three-fourths of the surface of 
Ireland. I need hardly say its existence is due to intense cold, 
and the action of immense glaciers which passed over the country, 
scoring the rocks, and, as Miller says, planeing down the surface of 
the land, and scooping out hollows, which afterwards became the 
beds of lakes. This, I believe, was the origin of the depression 
at Ballybetagh. The great ice sheet, which seems to have moved 
from the north-west, pushed over a hill lying at that side of the 
bog, and no doubt by its pressure coming down the hill excavated 
the hollow, sending the matter it had displaced over the next low 
hill, moving it onwards towards Enniskerry and the low grounds 
in that direction. The depression formed a catchment basin, and 
as the hills around it were naked of verdure, it soon began to fill 
with fine sediment, forming the stratified clay in which the 
Megaceros’ remains are found—in fact, becoming clay marl. The 
abundant vegetation seems to indicate a temperate climate, which, 
geologists teach us, succeeded the intense cold of the first glacial 
period. Hence, from the finding of the Megaceros’ remains in 
‘this lake sediment, I infer that the animal lived through this 
temperate period, called by Mr. Hull the second stage, or 
that of the sands and gravels—in fact, it lived imterglacially, 
and was almost the only mammalian inhabitant of the island. 
The moisture of these climates must have produced abundant 
verdure. It had few enemies. Paleolithic man may have existed 
in the country, but of this we have no evidence; but though he 
did exist, he could hardly with his rude weapons cope with this 
magnificent animal, The lon, tiger, and hyena were absent; 
the cave bear could hardly meet him in the field; and the wolf, 
almost his only enemy, might find it difficult work when we con- 
sider his speed, and the weapons of defence he possessed in his 
feet and antlers; while his habit of swimming lakes and rivers 
when pressed by his enemies,would contribute greatly to his safety. 
The next question now presents itself—the cause of its extine- 
