BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA 

 Vol. 28, pp. 419-430 JUNE 14, 1917 



THE SILVEE CITY QUAETZITES: A KA^^SAS METAMOEPHIC 



AEEA ^ 



BY W. H. TWENHOFEL 



{Presented before the Society December .27, 1916) 



CONTENTS 



Page 



lutroductiou 419 



Geology of the Silver City area 421 



The local section 421 



Lawrence shales 421 



latan (Kickapoo) limestone 421 



Le Roy shales 422 



Stanton limestones 422 



The Silver City anticline 422 



Detailed geology of Silver City ridge • 422 



Summary of the data 427 



Causes of the alteration 428 



Relation of the altered rocks to the lead and zinc deposits of southeastern 

 Kansas, the Rose boulders, and the granites reported from deep wells 

 of central Kansas 429 



IXTJiODL'CTIOX 



The Pemisylvanian section of Kansas and nei.uhboi'ing States is widely 

 known for the essentially unaltered character of tb.e composinii- sediments 

 and the supposed absence of any effects i-efcrablc to a,uents of i.iiJieous 

 origin. The discovery, therefore, ot evidence which proves ihat hvdro- 

 thermal nietamorphisin has affected sands ami sandy shales to the extent 

 of changing them to (piai'tzites is a fact of considci-able interest ami 

 iniportance.- 



The quartzites occur at Silver City,^ the eastern end of a long cast- 



le Manuscript received by tlie Secretary of the Society March 15, 1917. 



- The metamorphic rocks were noted long ago by Hay and Mudge, and, as subsequently 

 will be shown, the latter gave the correct explanation of the cause (see Trans. Kans. 

 Acad. Sci., vols, vii and viii. 18S1 and 1882). 



-■• Silver City received its name from the supposed occurrence of silver there, and 

 througliout the aren in tlie map within the lieavy line there are numerous old prospect 

 pits, some of wlii.b jnc said to hnvf attained depths cxceoding 100 feet. Tn 1870 a 



XXX Brr.L. Gy.n},. Sor. Ant.. Xn^.. J.S. lOKi (419) 



