BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA 

 Vol. 13, pp. 221-242 September 21, 1908 



GEOLOGICAL HISTORY OF TPIE EEDSTOXE QUAETZITE^ 



■ BY FREDERICK W. SARDESON 



{Presented by title before the Society December 30, 1901) 



CONTENTS 



Page 



Introduction 221 



The Archean or granitic rocks 22:? 



Tlie Courtland qiiartzite and the porphyrj- dil^e 225 



Tlie New Uhn hasal conglomerate : Camhrian 220 



The Big Cottonwood formation : Cretaceous 231 



Glacial drift and river deposits : Quaternary 2;ii> 



Character of the drift 23fi 



The Minnesota River valley * 237 



The Big Cottonwood valley 210 



Conclusion " 241 



References 242 



Introduction 



Eedstone, as it has Ijecn called for an indefmite numl^er of years, is a 

 conspicuous hill of quartzitic rock in the valley of the Minnesota river, 

 midway between the towns of New L"hn and Courtland. The aim of this 

 paper is to describe, geologically, this Redstone and the region which 

 immediately surroimds it. The name Eedstoue, as nsed here, has never 

 been employed as a geological formational name, and in the present paper 

 it will be used for the particular hill, Redstone, while the term Courtland 

 quartzite is the geologic formational name of the same rock. The old 

 village of Redstone, which stands at the foot of the quartzite hill, has 

 taken its name from that of the rock, rather than the name of the rock 

 from that of the village. 



The Redstone quartzite outcrops in an area of about 2 square miles 

 east of the village of Redstone, on the left side of the Minnesota river, 

 along the railway from New Ulm to Courtland, ilinnesota. It is a con- 

 spicuous feature in the valley because the hill of rugged quartzite rises 



1 Manuscript received by the Secretary of the Society March 23, 1908. 



XXII — Bull. Geol. Soc. Am., Vol. 19, 1907 (221) 



