168 0. Holtedahl — A Tillite-like Conglomerate. 



agmite, a pink, coarse, very often conglomeratic, thick- 

 bedded sparagmite, 300-400 meters thick, and in places 

 nrnch more. As to the conditions nnder which this and 

 the other beds of sparagmites have been formed, the large 

 amount of fresh feldspar necessarily presupposes, as has 

 been pointed ont by Walther and by several Norwegian 

 geologists, a weathering of granitic rock in a very dry 

 climate. That we are not dealing with wind-blown desert 

 sands is evident from the coarse and angular character of 

 the mineral grains, as well as from the absence of dune 

 stratification. There was here a very short and very 

 rapid detrital transport by torrential waters, from encir- 

 cling mountains into an intermontane basin, under semi- 

 arid conditions. The thickness of the beds, e. g., the red 

 sparagmite, the coarseness of the material, and the high 

 content of feldspar grains seemingly indicate a far shorter 

 length of transport and a much more rapid accumulation 

 than do the ordinary red sandstones of later formations. 



The red sparagmite is often seen to have conglomerate 

 zones with well rounded, water-worn bowlders of moder- 

 ate size. This passes upward into a more peculiar con-^ 

 glomerate to which I should like to draw special atten- 

 tion. It has a dark reddish brown color, with no visible 

 bedding at all and with fragments of all sizes embedded 

 in a fine-grained matrix. The smaller fragments are 

 generally quite angular and often the larger bowlders, 

 some of which are more than 0.5 meter in diameter, are 

 only partially rounded. The greater part of the frag- 

 ments consist of granites, gneisses, sandstones, and 

 quartzites. In addition, there are limestones, as in the 

 western district where this conglomerate is found at Lake 

 Mjosen, while in an eastern area, north of Trysil near the 

 Swedish frontier, occur porphyries of types known from 

 the pre-Cambrian still farther east. The limestone 

 bowlders mentioned are quite like those previously spoken 

 of as occurring in the Sparagmite division. 



The conglomerate just described 4 has all of the general 

 characteristics of a tillite, and it is difficult to think of any 

 other method of transportation for material of this kind 

 than a glacial one. As yet, however, no undoubted glacial 



4 An illustration of a specimen of the conglomerate is given in a paper by 

 the present author, ' ' Om Trysilsandstenen og sparagmif avdelingen, ' ' Norsk. 

 Geol. Tidsskrift, 6, 38, 1920. 



