48 



Paradoxides 

 in this divi- 

 sion. 



Curving 

 course of 

 measure on 

 McLean 

 brook. 



Jphannian 

 division in 

 Mira valley 

 concealed by 

 heavy cover- 

 ing of drift. 



about 150 feet of dark gray slates of the Acadian division, of which 

 the base is concealed by surface deposits and woodlands. 



Of the Johannian there are about 1,060. Of this thickness 365 

 feet in the lower part may be assigned to the section a ; in it there are 

 some heavy quartzite beds which have given rise to a fall : on the upper 

 part of the stream ; the lower half of this, above the falls, has much 

 dark slate interstratified. 



The middle section b, of about 455 feet, is mostly composed of flags 

 and slates, and is more f ossilif erous ; a Lingulepis allied to L. Starri of 

 the corresponding horizon in New Brunswick, is quite plentiful ; and a 

 Beyrichia, Beyrichia triceps, n.sp., with a high anterior ridge on the 

 valve, occurs. In the upper part of this section Mr. Loper found a few 

 examples of a variety of Paradoxides Forchhammeri, It differs from 

 the typical form in being smooth on the glabella, but it is warty on 

 the slope of the cheeks like that form. 



The upper section (c) of about 245 feet is composed of softer and 

 more micaceous flags and slates, in which fossils were not found so 

 abundantly ; those that occur are of smaller size than the species of 

 the middle band. Following these and resting upon them are black 

 and dark-gray fine, soft, crumbling slates that have a considerable 

 width, and are the last rocks exposed in going down the stream. 

 These would belong to the Bretonian division. 



The section of this brook shows the same curving of the strata 

 around the McCodrum ridge as Mr. Fletcher noticed in the Etche- 

 minian terrane on McCodrum brook. In the lowest exposures of the 

 dark gray Acadian slates on the upper part of McLean brook the dip is 

 S. 40 E. inag. ; at the falls in the quartzites, etc., of the lower section 

 (a) it is S. 60 E. mag. ; higher measures of the same section return 

 to S. 40 E. mag. ; in the middle section the dip varies from S. 5 J E. 

 mag. to 40 E. mag. ; in the upper part of this section it changes to 

 S. 20 E. mag., and so continues to the top of the Johannian division. 

 The change of strike is about forty degrees, which agrees with the 

 change observed by Mr. Fletcher on McCodrum brook. 



The sections of the beds of the Johannian division, seen elsewhere 

 in the Mira valley, are so partial, owing to the heavy drift covering in 

 this valley, that no satisfactory proof of the thickness of this member 

 was met with, other than in this section, but it will be noticed that 

 this section agrees nearly in the thickness of the beds with those 

 exposed on McMullen brook in the Indian Brook valley. 



