GEOCHROlSrOLOGY DE GEER 695 



In order to connect archeological finds with the time scale, several 

 different phenomena can be used. Thus, the situation of the ice 

 border at different stages of its recession can be dated and mapped, 

 whereby it is possible to date cultural remains as well as traces of 

 animals and plants, which immediately followed in the track of the 

 retreating ice. This can probably be done in the case of the Quater- 

 nary ice-dammed Lake Pulawy, which was discovered by N. Krichta- 

 fowitch, southwest of Warsaw, between the Vistula and the Bug. 

 This lake reached as far as the limits of the last glaciation and its 

 sediments, showing no varves, are covered by the last moraine and 

 contain remains of plants and animals, including Elephas primi- 

 ffsnius, Rkinoceros tichorhinus, Bos priseus, Equus cabaUus fossilis, 

 and jSus scrofa fossilis; also pieces of bone, and flint tools which were 

 referred by S. Krukowski to the Solutrean epoch. 



It is obvious, however, that all attempted coordinations founded 

 only on the occurrence of certain organisms must be merely approxi- 

 mate. Amongst the more reliable geophysical phenomena a first place 

 will doubtless be occupied by such ancient shore lines as can be dated 

 with some accuracy and are adapted for the dating of prehistoric re- 

 mains, especially those pertaining to shore dwellings. It is true that 

 positions of the edge of the retreating ice can be dated with still 

 greater accuracy, but, in the central parts of northern Europe at least, 

 human occupation had not begun at that time. During the last few 

 years it has been found possible, by a new method of investigation, to 

 follow step by step, and fix by levelling, the present height of a series 

 of unevenly uplifted shore lines dating from the nordic Bronze and 

 Stone Ages. These measurements, which I started some years ago 

 in the Stockholm-region, now embrace the greater part of the Neo- 

 lithic marine area within the eastern-central parts of Sweden from 

 Ostrogotia to the south of Helsingland. In this way very reliable 

 and detailed knowledge can be obtained concerning the withdrawal of 

 the coast line and the growth of the emerging land. It has also been 

 found possible to connect the different stages of coastal evolution 

 with the Swedish time-scale, and so to date approximately all the 

 phenomena which can be connected with such coast lines. 



The question of eustatic shore lines seems to be more complicated 

 and has not been brought into any connection with geochronology. 



On the whole it seems desirable that relative as well as approxi- 

 mate time computation,s should be expressed in another way than real 

 datings and without figures, which give a misleading impression of 

 precision and certainty. 



