166 P. A. ØYEN [1914 



First Period of Valley Glaciation, 



Second Period of Vallej' Glaciation, 



Formation of Terrace-steps. 

 Og her uttaler han ganske Hketil: >Periodic changes of climate 

 in post-Glacial time brought about minor stages of alluviation 

 and degradation with the production of the present terrace-steps, 

 gorges, and ravines« (Drysdale: Geology of Frankhn Mining 

 Camp, British Columbia, 1915, pag. 13). Og samme forsker 

 uttaler videre: »Without further climatic variations Ihere would 

 be a single cycle of degradation and no terraces except those 

 due to the normal sidewise swinging of the streams. This is 

 not the case in the Franklin district, for periodic changes of 

 climate in post-Glacial lime have brought about minor stages of 

 alluviation and degradation. Such climatic oscillations are in- 

 ferred on accounl of the presence on both sides of the Franklin 

 valley, near its junction with the main Kettle valley, of a series 

 of terrace steps« (L. c. pag. 26). Det har sin store interesse her, 

 i motsætning til den tidligere efter Upham anførte opfatning, og- 

 saa fra amerikansk side at tinde uttryk for en mere med nyere 

 europæiske opfatninger samstemmende anskuelse, hvilket vi jo 

 ogsaa ganske naturlig maatte vente, naar vi erindrer, at allerede 

 for omkring en menneskealder siden giorde Salisbury opmerksom 

 paa den store likhet mellem de til Mecklenburgian i Europa 

 og til Wisconsin i iVmerica svarende endemorænelandskaper i 

 en af handling: > Terminal Moraines in Northern Germany « (Ame- 

 rican Journ. 'Sci., Vol. 85, 1888, pag. 401—407). Dette' har da 

 ogsaa senere og i mere utvidet form fundet uttryk i Leverett's 

 afhandhng: »Comparison of North American and European glacial 

 deposils< (Zeitschr. fiir Gletsherkunde, B. IV, 1910, pag. 304 flg.), 

 hvor han behandler the fourth drift«. For os har del i denne 

 forbindelse en speciel interesse, at Leverett ved hin anledning 

 kommer til det resultat, at »the moraines of the Wisconsin drift 

 admit of grouping in a way thai suggest sladia similar to those 

 described by Penck and Bruckner in the Alpine region. East 

 group consists of a bulky outer moraine which seems to be 

 merely recessional and to indicate no readvance of the ice border. 

 The bulky outer moraine of the group, however, is thought to 

 indicate a readvance of more or less consequence, for it is not 

 entirely concentric with the moraines outside of it« (L. c. pag. 306). 

 Særlig bør vi her merke os Leveretts ultalelse: »It can scarcely 

 be decided in the present state of investigation whether the groups 

 of moraines in the Wisconsin drift of America correlate with the 

 several stadia in the Alpine region, but it certainly is a sugges- 

 tive feature of resemblance« (L. c. pag. 306). I umiddelbar til- 

 slutning hertil har det derfor ogsaa sin store interesse at minde 



