310 Proceedings. 



ern shore of the glacial lake Agassiz it is mostly very fine gravel, and 

 mostly of limestone. Around some of the present lakes in these counties 

 the gravel and shore sand are mostly limestone. Around lake Oscar, in 

 Wilkin county, the finer gravel and smaller pebbles are certainly as much 

 as three-fourths limestone, while 20 to 50 miles further east and north- 

 east in the neighborhood of the range of hills known as the Leaf hills, 

 there are many limestone bowlders, some of them rounded but others are 

 more or less angular, showing little wear ; some weigh a ton or more, yet 

 far the greater number of them are not larger than one can lift. They are 

 all white limestone, probably of Devonian age, and make a good lime. 

 These bowlders are being collected and burned into lime so fast that they 

 will soon be gone. There are fossils in all of them. I have seen pieces 

 of crinoid stems in the gravel. The drift is not less than 500 to 600 feet 

 thick in parts of Ottertail, Grant and Douglass counties, and no doubt 

 thicker than that in the Leaf hills. It is difficult to find clay free enough 

 from calcium carbonate for brickmaking in the counties mentioned. Even 

 the clay will effervesce strongly in acids. There is a stratum containing 

 limestone gravel lying under a sandy surface around Ottertail lake and 

 the Battle lakes which lie beyond the Leaf hills from lake Agassiz, and 

 some 50 to 60 miles away. It seems as if the siliceous deposit had drifted 

 in later than the calcareous. 



Secretary Hall remarked as follows : 



[abstract.] 



The discovery of Paleozoic fossils in the glacial drifts of Minnesota 

 and Wisconsin, is one of no little geological significance. It has been no 

 uncommon thing around Minneapolis and St. Paul to find winrows of the 

 blue Lower Silurian fossiliferous shale piled up within the mass of drift 

 material without being commingled with the gravel and sand from the 

 older crystalline rocks; and the occurrence of fossils in the drift material 

 to the south of the northern border of the Paleozoic should naturally be 

 expected. When, however, specimens are found to the north of this bor- 

 der the significance is much deeper, and particularly so since there are no 

 known beds of Paleozoic limestones in the northern part of the two states 

 named, nor in Ontario within 100 miles of Lake Superior, according to Dr. 

 A. C. Lawson. To the westward, however, there are many basins filled 

 with still imdisturbed Paleozoic rocks, which, in the opinion of that writ- 

 er, are but fragments of what was once an extensive bed."^ With such 

 evidence for the surface to the north of Minnesota, and the constanth^ 

 accumulating evidence which drift fossils show touching conditions within 

 the state, we are forced to conclude that the northwestern states were to a 

 large extent beneath the sea in early Paleozoic times. 



March 3, 1 891 . 



Twenty-nine persons present. 



*Note on the Pre-Paleozoic Surface of the Archaen Terranes of Canada. Bull. 

 Geol. Soc. Am; Vol. i, p. 169. 



