244 EXTINCT MONSTERS. 
Mr. W. Williams, who has explored several peat-bogs in 
Ireland, marking the site of ancient lakes, and found many 
specimens in beds underlying the peat, has given much interest- 
ing information bearing upon the question of the period when the 
Great Deer inhabited Ireland, and the manner in which it was 
preserved in the lake-beds.1 He spent ten weeks in 1876-77, 
excavating deer remains in the bog of Ballybetagh, and subse- 
quently made similar excavations in the counties of Mayo, 
Limerick, and Meath. These peat-bogs occupy the basins of 
lakes, the deeper hollows of which have long since been silted up 
with marls, clays, and sands, and in this silt, or mud, the plants 
which produced the peat grew. In all the bogs examined he 
found a general resemblance in the order of succession of the 
beds, with only slight variations in the nature of the materials 
such as might be easily accounted for by differences in the 
surrounding rocks. In these deposits the geologist may read, as 
in a book, the successive changes in climate that have taken 
place since the time when the country was deeply covered with 
snow and ice during the Glacial period. 
He found at the bottom of the old Ballybetagh Lake, and 
resting on the true Boulder Clay (a product of the ice-sheet), a 
fine stiff clay which seems to have been brought in by the action 
of rain washing fine clay out of the Boulder Clay, that nearly 
covered the land, and depositing it in the lake. This action 
probably took place during a period of thaw, when the climate 
was damp, from the melting of so much ice, and the rainfall con- 
siderable. ‘Then the climate improved, the cold of the Glacial 
period passed away, and the climate became warm. During this 
phase the next stratum was formed, consisting chiefly of vege- 
table remains. ‘The summers must have been unusually warm, 
dry, and favourable to the growth of vegetation on the bed of the 
lake. About this time the Great Irish Deer appeared on the 
scene, for its remains were found resting on this layer, or stratum, 
2 Geological Magazine, new series, vol. viii. (1881), p. 354+ 
