BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA 



Vol. 25, pp. 265-276, PL. 12 JuNE 29, 1914 



CHAEACTERISTICS OF A COEROSION CONGLOMERATE^ 



BY FREDERICK W. SARDESON 



{Bead before the Society December 30, 1913) 



CONTENTS 



Page 



Introduction 265 



General discussion . ' 265 



Formational relations 268 



Corrosion surfaces 268 



Corrosion conglomerate 269 



Conglomerate in the Galena formation 269 



General description 269 



Origin of limestone pieces in the shale 270 



Condition of the shale on the sea-bottom 271 



Fucoids 271 



The work of sea-weeds 272 



Characteristics of corrosion conglomerate 273 



General characteristics 273 



Composition of pebbles 273 



Color 273 



Surface of pebbles 274 



Amount and distribution 274 



Preservation 275 



Conclusion 275 



Introduction 



GENERAL DISCUSSION 



The conglomerates of the Galena-Trenton series of the Ordovician 

 have been once before described^ in an article in the American Geologist. 

 At that time those conglomerates were interpreted as intraformational in 

 contradistinction to basal or interformational conglomerate.^ They were 



1 Manuscript received by the Secretary of the Society December 31, 1913. 



2 P. W. Sardeson : Intraformational conglomerates of the Galena series. The American 

 Geologist, vol. 22, 1898, p. 315. 



3 Charles D. Walcott : Paleozoic intraformational conglomerate. Bull. Geol. Soc. Am., 

 vol. 5, 1894, p. 191. 



(265) 



