PLATE LXVII. 



THE NORTH PART OF ST. Louis COUNTY, 1899. N. H. WINCHELL. 



This area is crossed from northeast to southwest by the Giant's range of granite, 

 and is entered by the Mesabi range of gabbro from the northeast at a point about 

 two and a half miles south from the entrance of the Giant's range. The Mesabi range 

 does not continue on its westward course but veers off more southerly, and is lost, as 

 a "range," in the general upland which is drained by the headwaters of the Cloquet 

 and the St. Louis rivers. The same rocks appear again on some of the branches of 

 the Cloquet and at Duluth. Owing to the fact that the earliest developments of 

 iron ore were on the northern slopes of Mesabi range, that name was given to the 

 southern iron ore range, and it has been continued westwardly, although the iron- 

 bearing rocks, in their westward extension, lie on the southern flank of the Giant's 

 range and are far separated from the Mesabi range proper. 



Between the Giant's range and the Mesabi range, in the angle formed by their 

 divergence, is an expanse of flat and largely swampy land, which was formerly occu- 

 pied by the glacial lake Upham, as explained in connection with Plate LXVI. East- 

 ward from that flat land, and, indeed, in all directions, the drift-covered surface rises 

 gently, at first mainly flat, but becoming rough and morainic. On the gabbro area 

 this roughness is due in part also to the irregularity of the rocky contour, and it 

 surrounds some large muskegs, such as are crossed by the Duluth and Iron Range 

 railroad. Northward from lake Upham a distinctly morainic tract follows approxi- 

 mately the course of the Giant's range, that range apparently being the barrier along 

 which the Lake Superior ice-margin lay for a long time after the withdrawal of the 

 continental margin toward the north. It is also likely that this moraine was at an 

 earlier date the line of confluence of the two ice-lobes, as indicated by the alterna- 

 tion of northern and Lake Superior till deposits at various points on the Giant's range. 

 The Embarras river maintained a southward discharge through this moraine, and 

 wholly across the Giant's range, by way of the Embarras lakes, whereas the Pike 

 river, rising on the Giant's range but five or six miles further west, flows northward 

 to Vermilion lake. These streams formerly probably united in a glacial lake which 

 incidentally must have extended eastward nearly to Birch lake, and which covered 

 a large flat tract now drained by the Embarras river, characterized in places by 

 laminated brick clay. Its outlet is crossed by the old portage leading from Pike 

 river to Embarras river, in the southwestern part of T. 60 15, which is broadly ter- 

 raced. The shores of this lake remain to be traced out. The lake itself might be 



