PLATE XLVII. 



STEARNS COUNTY, 1888. WARREN UPHAM. 



The Archean rocks noted in connection with Benton and Sherburne counties 

 (Plate XLVI) continue westward and extend everywhere under Stearns county. 

 They appear in outcrop in Ashley, in the extreme northwest and in Saint Augusta 

 in the southeastern town of the county, also at many intermediate points. These 

 rocks, as exposed, are chiefly granite, syenyte, dioryte, with a little mica schist.* It 

 is highly probable that if the drift could be removed the schists would be found much 

 more common. Their more destructible nature has caused them to be decayed and 

 eroded. They therefore are most likely to occupy the depressions in the preglacial 

 surface, and these depressions are also the places where the drift deposits were most 

 likely to be left, whether by the ice or by the floods of the glacial epoch. 



At several places in Stearns county these rocks are wrought for use in all places 

 in which granite is applicable. The quality of some of these granites has been given 

 in volume I, in the chapter devoted to the building stones of the state. 



The drift features of this county are quite complex. The northwestern and 

 northeastern ice-lobes of the last glacial epoch appear to have occupied this area 

 sometimes jointly and in some places alternatingly. The drift of the earlier glacial 

 epoch has not been satisfactorily differentiated from that of the later. Belts of 

 morainic drift run somewhat irregularly through Stearns county. These probably 

 are in part medial moraines and in part terminal, and all of them belong to the last 

 glacial epoch. The east half of the county, speaking generally, is characterized by 

 the northeastern .drift and the west half by the northwestern; but in some places 

 the color and characters of the northeastern have in a measure faded out. There 

 was, further, a later advance of the northwestern ice further east, even as far as the 

 Wisconsin boundary, and the retreat of this ice-lobe left a large amount of north- 

 western till and gravel and sand, much further east than the centre of the county. 

 This is continuous with similar deposits mentioned in Wright, Benton and Chisago 

 counties. These later deposits uniformly lie upon red drift from the northeast. 



It was at a still later date that a glacial river of considerable size, now dried 

 up, flowed across Stearns county, as mentioned in the description of the plate of 

 Kandiyohi and Meeker counties, draining from the still existing ice-fields of the 

 counties further northwest. Its abandoned valley lies in Zion, Munson, Wakefield 



'Detailed description* of the rocks at Watab, Sauk Rapids and Sank Center will be found in the Eli-mit/i Animal A'> /x,<7, 

 1883, p. 71. Observations on the field relations made at Sauk Center are published in the Thirteenth Alumni HI i><,i-t, 1884, p. 11. 

 Rocks collected at Sauk Center are described also in vol. v, pp. 5fi6, 574. The St. Cloud granites are described in vol. v, pp. 550-552; 

 564, 838. 



