PROCEEDINGS 



OF THE 



WASHINGTON ACADEMY OF SCIENCES 



Vol. I, pp. 301-339. February 14, 1900. 



LOWER CAMBRIAN TERRANE IN THE ATLAN- 

 TIC PROVINCE. 



By Charles D. Walcott. 



CONTENTS. 



Introdaction . 301 



Description of Sections 305 



Unconformity at base of St. John Group 324 



Lower Cambrian Fauna 331 



Nomenclature 338 



Conclusions 339 



Introduction. 



Since the publication of the correlation memoir on the Cam- 

 brian, in 1891/ a number of articles by Mr. G. F. Matthew- 

 have appeared from time to time advocating the dropping of 

 the term Middle Cambrian and using the two terms Upper 

 Cambrian and Lower Cambrian, the Lower Cambrian to in- 

 clude the Middle Cambrian (Paradoxides beds) and strata 

 containing the subjacent 'Protolenus' fauna, which was regarded 

 as the equivalent of the Olenellus fauna. ^ Mr. Matthew was 

 led to advocate this division of the Cambrian largely by reason 

 of his failure to find the Olenellus^ fauna in the ' Basal or 



iBull. U. S. Geol. Survey, No. 81. 



* Matthew, G. F., The Protolenus Fauna: Trans. N. Y. Acad. Sci., Vol. XIV, 

 1895, p. 103 ; A New Cambrian Trilobite : Bull. Nat. Hist. Soc. New Bruns- 

 wick, No. XVII, 1S99, p. 142 ; Studies on Cambrian Faunas, No. 4 : Trans. 

 Roy. Soc. Canada, 2d sen, Vol. V, 1899, Sec. IV, p. 8 ; Preliminary Notice of 

 the Etchemiuian Fauna of Cape Breton : Bull. Nat. Hist. Soc New Bruns- 

 wick, Vol. IV, 1899, pp. 198-208. 



»Am. Jour. Sci., 3d sen, 1889, Vol. XXXVII, pp. 374-392 ; Vol. XXXVIII, 

 pp. 29-42. 



Proc. Wash. Acad. Sci., February, 1900. (3^0 



