BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA 



Vol. 12, pp. 301-312, PL. 26 AUGUST 16, 1901 



KNOYDART FORMATION OF NOVA SCOTIA* 



BY HENRY M. AMI 



( Read before the Society December 28^ 1900) 



CONTENTS 



Page 



Introduction 301 



Typical area under discussion ,. 301 



Contact of Silurian and Devonian strata 302 



Classification and views of various writers , 302 



Discovery of fossils and their interpretation. ..."., .*. 304 



Fletcher's section of the Knoydart formation along Mc Arras brook , 306 



Name and fauna of the Knoydart formation , 309 



Barlow's description of volcanic ash rock 309 



Paleontologic notes and faunal relations indicated 310 



Conclusions 312 



Introduction 



While engaged in making a paleontological survey of the rock forma- 

 tions of the Upper Paleozoic in Nova Scotia, and also studying material 

 placed at his disposal from previous collections in the Geological Sur- 

 vey Department, the writer has discovered what appears to be sufficient 

 evidence for the determination, of the geological horizon of a series of 

 strata which occur in the western corner of Antigonish county, extend 

 into the adjacent county of Pictou, Nova Scotia, and measure probably 

 not less than 1,000 feet in its greatest development. One of the best 

 natural sections where this series may be examined and studied to ad- 

 vantage occurs in the valley of erosion through which flows McArras 

 brook. A measured section recently made by Mr Hugh Fletcher, of the 

 .Geological Survey of Canada, and cited below, gives a total thickness 

 of 684 feet. The strata in question are placed in the Lower or Eo-Devo- 

 nian, inasmuch as they contain fossil remains characteristic of the typical 

 " Old Red Sandstone " of Europe. 



Typical Area under Discussion 



On sheet-map number 34 of the series of geological maps of Nova 

 Scotia, issued by the Geological Survey of Canada in 1893, there is rep- 



* Published by permission of the Director of the Geological Survey of Canada. 

 XLIII— Bui.i-. Geol. Soc. Am., Vor,. 12, 1900 , (301) 



