344 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1917. 



beaches, they are of approximately the same age as the cold periods, 

 and they are shallow water sands at present a little below sea level 

 at Belfast, but rising above it farther west. 



Curiously enough, this change in the relative levels of Belfast 

 and Malin Head has also left a trace in tradition, namely that Lough 

 Neagh was formerly smaller, but its shores subsided, carrying human 

 habitations below the waters. The area was the scene of great 

 volcanic activity in Tertiary times, and the traditional subsidence 

 may be the last of several in postglacial times which carried the 100- 

 foot beach of Belfast down to sea level. 



SUMMARY. 



I. Glacial. — Raised beach of South Ireland. Bowlder clay of 

 Kill o' the Grange and gravels of Baltybrack. 



I. InterglaciaZ. — Peat of Newtown. 



II. Glacial. — 1. Lower bowlder clay. 2. Midglacial gravels. 3. 

 Upper bowlder clay. 4. 100-foot raised beach. 5. Moraines of large 

 valley glaciers. 



II. Intert/ltirhil. — Lacustrine marls, etc., of Ballybetagh, etc., with 

 Irish elk. Earlier submerged forest (northeast Ireland). 



III. Glacial. — Moraines of small valley glaciers. Detrital de- 

 posits of Ballybetagh, etc. "Head" of south coast. 50-foot beach 

 and gray sands of northeast coast. Arctic bed of Isle of Man. 

 Lower peat bed. 



Warm wet period. — 25-foot raised beach with southern fauna. 

 Warm dry period. — Pine forest. Extension of trees up mountain 

 sides. Elevation and formation of later submerged forest. 

 Recent period. — Upper peat. 



8. THE POSTGLACIAL HISTORY OF THE LAND AREAS OP NORTHERN 



EUROPE. 



After the melting of the ice of the last glacial period in Germany, 

 north Russia, and the Scandinavian countries, various terrestrial 

 deposits were formed which throw light on the subsequent climatic 

 history of the district. Chief among these are the peat bogs, which 

 have been studied in great detail, in Norway by J. Holmboe and 

 P. A. Oyen, in Sweden first by A. Blytt, later by Gunnar Anders- 

 son and R. Sernander, in Finland by H. Lindberg, and in Germany 

 by J. Stoller and C. A. Weber. 



It is in Sweden that the question of the existence and meaning 

 of "forest layers" in the peat bogs has been most critically discussed. 

 The succession made out by A. Blytt (107) was as follows, the oldest 

 period being at the bottom : 



