Etcheminian 

 at Spruce 

 brook. 



Cambrian 

 strata on 

 Gillis' brook. 



Worm bur- 

 rows and 

 rippled flags. 



Bretonian 

 division. 



Section of 

 Johannian 

 at McLean 

 brook, Mira 

 river. 



There is a considerable area of Cambrian rocks near the head of 

 East bay, on its northern side, which was examined ; it extends from 

 Spruce brook to Gillis brook. At the first brook, exposures are 

 limited in extent in the western tongue of a basin covered on the 

 east and south by Lower Carboniferous deposits. On the west branch 

 of Spruce brook at the foot of the granite hills are purplish gray 

 sandstones containing valves of Lingulella and Acrotreta ; these beds 

 dip N. 10 E mag. < 50 ; they may be assigned to the Lower 

 Etcheminian. There are some beds of felsite and of felsite-grit inter- 

 calated with these sandstones. 



An examination of the Cambrian areas on Gillis brook was made 

 above and below the point where the Coxheath road crosses it. (See 

 map on preceding page.) At this point there is a width of 2,000 feet 

 or more of the Johannian division, much folded and crumpled. Above 

 the bridge at the Coxheath road th^re is a large quantity of gravel 

 and boulders along the stream and the ledges are seen only at intervals. 

 Below the bridge the stream has cleaned out its valley, and runs with 

 a tortuous course through a ridge of quartzites and flags to a flatter 

 tract where it has a more regular flow through rounded hills of black 

 and dark-gray shale of the Bretonian division, whose measure^ have a 

 width on the surface of 1,500 feet. 



Below this the stream crosses another band of the gray flags of the 

 Johannian division and again becomes more tortuous, with high banks 

 until it meets Lower Carboniferous feldspathic conglomerates. The 

 flags and slates have worm galleries of Arenicolites and pits marking 

 the lairs of Monocraterion. Ripple-marked and wave-marked flags 

 are present here, with spaces of three to five inches between the crest 

 of the wave ridges. In the dark gray shales of the Bretonian division 

 further up stream there are a few thin limestone beds and lentiles, in 

 one of which valves of Orlhis lenticularis are plentiful. 



The lower part of the St. John group was not seen, nor was any 

 older Cambrian terrane observed, this Cambrian area being separated 

 on both sides from the pre-Cambrian rocks by Lower Carboniferous 

 deposits. The best section of the Johannian division of the St. John 

 terrane in the Mira valley is that exposed on McLean brook, near 

 Marion bridge. This section has been exploited by Mr. S. Ward 

 Loper, who has collected there extensively for the United States 

 Ge'ological Survey. (See map on opposite page. ) 



Here the whole series of the flags and slates of this division are 

 exposed in the valley of the brook, which cuts across them transversely. 

 They dip down the stream at an angle of 70 to 50 and rest upon 



