/4 



CONTENTS 



Page. 

 Lkttkr op Transmittal xiii 



UirrLI.NE OF THIS PaPKH XVII 



Introditction 1 



Chapter I. — (iEouKiicAi. Explorations and LrricuATtiUK 5 



GeolDRiiiil cxploiatioii in the district, p. 5. Barnes (1817),«ii. ">. Whitney and Barnes 

 (1847), p. 6. Randall (18-IS), ].. 7. Whittlesoy (18J9 and 18t;(»), p. 7. Lapliam (1858), 

 p. 7. BrooksaudPunipeny(1871),p. 8. Irviufj (1873, 1870. 1877, 1885), p. 8. Wight, 

 Sweet and W^right (1875),p.9. Wright (187C), p. !l. Chanilicrliu (1877), p, 9. Con- 

 over (1878), p. 10. Roniinger (1882), p. 10. Van Hise (1884-1887), p. 10. Ohjeit of 

 the woi;k under the V. S. Gcologiial Survey, p. 10. Amiotated list of tlie literature 

 of the snbject, p. 13. 



Chaptkk II. — The Soitheux Compee.x 103 



General, p. 103, Geographical distribution, p. 104. The Western grauiti;, p. 106. The 

 Western green schist, p. 107. The Central granite, ji. 111. The Eastern green schist, 

 ](. lie. The Eastern granite, p. 122. Summary, p. 122. 



CiiAi'TKR III. — The Cherty Li.mestonh 127 



Relation of the limestone and chert, p. 127. Geograi)hical distrilmtion, p. 128. Pos- 

 sible former greater continuity, ]>. 129. Thickness, p. 130. Petrographical character 

 of the limestone, p. 130. Petrographical character of the chert, p. 132. Change to 

 the overlying Qiuirtz-Hlate, p. 134. Tabulation of ])etrographical observations, )i. 

 134. Prominent e-vposures, p. 138. Origin of the limestone and chert, p. 140. 

 Sunnuary, p. 141. 



Chapter IV.— The Qiartz-Si.ate Member 143 



Applicability of the name, p. 143. Geographical extent, p. 144. Topographical fea- 

 tures. i>. 145. Thickness, p. 140. General petrographical character and stratigraphy, 

 p. 14t). Microscopical character of the feldspathic (luartz-slates, p. 140. Micro- 

 scopical character of the biotitic and chloritic (inartz-slatcs, p. 151. Microscoj)i(al 

 character of the vitreous quartzite, p. l,^3. Microscopical character of tlie sand- 

 stone, novacniite, and argillaceous slates, p. 154. Tabulation of petrographical 

 observations, p. 155. Contacts with the Cherty limestone member, p. 171. Con- 

 tacts with the Southern C'omidex, p. 172. Change to the Iron-bearing member, ]>. 

 175. Prominent exposures, p. 175. Mode of deposition and source of material, 

 p. 170. Summary, p. 180. 



Chaptku V. — The Iron-bearing Member 182 



Section 1.— Details , 182 



Applicability of the n.ame, p. 182. Abruptness of transition from the underlying 

 Quartz-slate member, p. 184. (ieographical extent, p. 185. To)iographicaI features, 

 p. 188. Thickness, p. 189. General peti'ograpliical character, p. 190. Distribu- 

 timi of the three types of rock, p. 198. Microscopical character of the cherty iron 

 carbonates, p. 200. Micniscoiiical character of the feriugiuous slates and ferruginous 

 cherts, p. 202. Microacopiciil cliaracter of the actincditic slates, ]i. 210. Tabulation 

 of petrographical observations, ]). 215. ' v 



