44 



Plumbaginous. At the rnouth of Dugald brook, a little further down the valley, a 

 mouth of narrow band of black plumbaginons slates shows itself next the granite. 

 Dugald brook. These would belong to the Bretonian division, so that there is reason 

 to suppose that this twelve hundred feet of the section on McMullin 

 brook represents the whole of the Johannian division as it is developed 

 in the Indian brook valley. An examination of Indian brook from 

 the mouth of Dugald brook downward shows little beside the Johan- 

 nian division. For two miles, or as far as the highway bridge, the 

 channel runs close to the foot of a high ridge of pre-Cambrian syenite, 

 with exposures of flags, quartzites and arenaceous slates in the bottom 

 of the valley. They vary somewhat in strike, but generally this is 

 parallel to the course of the stream. 



On Indian These beds are sometimes overturned, as is shown by the worm- 



are ripple burrows and wave marks on the flags. The ripples are occasionally 

 marked flags. p ira ii ft } to the course of the stream (and valley) and at other times at 

 right angles to it. No such wave-marks could have been produced by 

 waves transverse to the course of this narrow valley, if the contour of 

 the land had then been such as it is now. The hills whi^h bounded 

 the valley in Etcheminian time had at this epoch of the Cambrian 

 passed below sea-level, and the Cambrian deposits made in it were 

 subject to the mouldiag influence of the ocean waves. 



Cambrian Below the highway bridge the Cambrian flags and quartzites form 



depressed be- an anticlinal fold, of which the eastern slope is depressed toward the 



tween syenite . . * 



ridges. southern syenite ridge, and the western is cut on by an encroaching 



syenite ridge on the opposite side of the valley. These two ridges meet 

 a mile above the mouth of the stream, so that the Cambrian basin 

 terminates here abruptly. As neither the Coldbrook nor the Etche- 

 minian terranes are seen at this end of the valley, and as the lower 

 division of the St. John terrane is not in view, the whole Cambrian 

 must here have sunk many hundred feet along fault lines into the pre- 

 Cambrian complex. 



Johannian -^ limited outcrop of the flags of the Johannian division is found at 



division at Mclntosh brook on East bay, half a mile above its mouth. It con- 

 brook, sists of gray flags and shales in frequent alternations; dip S. 10 E. 

 mag. < 70. Loose pieces of the flags contain Lingulella (sp.) and 

 more rarely Acrothele (sp). Resting on these are gray rubbly shales, 

 soft and micaceous, with Arenicolites and other worm burrows. They 

 are cut off at the left bank by the crystalline volcanic rock mentioned 

 by Mr. Fletcher. The Cambrian area is small and no other part of 

 the Cambrian terranes were seen here, as overlying Lower Carbonifer- 

 ous limestones and shales conceal their extension. 



