Nr. 6] KVARTÆR-STUDIER I TROiNDHJEMSFELTET 169 



Mellersta hvitåsand och hvitålera (YoIdia-\era, Gadus poIarisAenx) 



Undre morån 



Undre hvitåsand och hvitålera 



> Arctic freshwater-bed 



Undre }oW/a-lera och BridHnglon crag 



Cyprina-lera och Leda mijalis-\agrei 



» Skogen i Gromer « 



Norwich Crag 



Red Crag 



Coralline Crag. 



Dog maa vi her erindre, at allerede flere aar tidligere hadde 

 John William Dawson i sit » Supplement to the second Edition 

 of Acadian Geology<', London 1878, pag. 27 — 28, for Kanadas 

 vedkommende foreslaaet følgende Subdivisions of the Pleistocene 

 Deposits' : 



1. Peatj' terrestrial surface anterior to boulder clay 



2. Lower stratified gravels (Syrtensian) 



3. Boulder cla}^ and unstratified sands with boulders (Fauna 

 extremely Arctic) 



4. Lower Leda clay with highly Arctic shells 



5. Upper Leda clay and sand (Uddevalla beds, many sub Arctic 

 or boreal shells) 



6. Saxicava sand and gravel (with littoral shells of boreal or 

 Acadian types). 



Og Dawson omtaler ved samme leilighet »beds of Leda clay 

 passing upwards into sand and gravel< (L. c. pag. 28). Det 

 samme fænomen fremstilles ogsaa i »Reports on a Portion of 

 Algoma and Thunder Bay Districts Ontario « by W. J. Wilson 

 (Canada, Dept. of Mines, Geol. Surv. No. 980 (1909), pag. 31—32), 

 hvor der meddeles: >The w^hole county is deeply covered with 

 clay through which the rivers have cut deep, canal like chan- 

 nels, in places to a depth of 40 or 50 feet. The clay banks 

 frequently show a distinct line of separation about midway up. 

 The lower half is hard and usually stands at a steeper angle 

 than that above, and contains many large and small striated 

 boulders. The upper part shows stratification, and for a con- 

 siderable distance from the mouths of the rivers holds marine 

 shells, Saxicava rugosa being especially abundant, and Macoina 

 calcaria and Mya arenaria are also fairly common. On the 

 Nagagami the shells were found about seven miles irom the 

 mouth, but above this, although the clay seemed the same, no 

 shells were found. On the Kebinakagami they were seen for 



twelve miles up this clay is evidently the equivalent 



of the Leda clay of eastern Canada «. Jeg har git et saavidt ut 

 førligt citat af den interessante beskrivelse netop fordi vi her 



