802 SIE J. W. DAWSON ON THE EOZOIC AND PALEOZOIC 



Passing from Newfoundland to the coast of southern ISTew Bruns- 

 wick, we find iu the " Coldbrook " and " Coastal" series of Bailey a 

 group corresponding essentially to that in j^ewfoundland, except 

 perhaps in the fact that felsitic rocks occur to a larger extent in the 

 lower part, and that the upper part presents not only conglomerates, 

 ash-rocks, and amygdaloids, but also chloritic and hydro-mica schists. 

 This upper part, distinguished as the " Coastal Series," is regarded 

 by Prof. Bailey as distinct from the Huronian proper, and as either 

 an upper member of that system or perhaps of later age, though 

 pre-Cambrian *. 



As in Newfoundland, the typical Huronian of New Brunswick is 

 overlain by reddish and purple conglomerates, sandstones, and shales, 

 which are, however, here regarded as the base of the Cambrian t. 

 llatthew has recently found in them not only worm-burrows and 

 fucoids, but a LinguLoid shell. They appear, however, to underlie 

 un conformably the lowest division of the Paradoxides-beds. 



With these rocks, whether of Lake Huron, Newfoundland, or New 

 Brunswick, I have no hesitation in comparing the Pebidian of Wales, 

 as well as certain portions of the older Malvern rocks and those of 

 Charnwood Porest. Some of these groups I have seen on the ground, 

 others are well known to me by suites of specimens. Similar rocks 

 also succeed the Laurentian in Scandinavia and in other parts of 

 Europe as well as in Africa and portions of Asia. Thus the 

 Huronian tj^pe is very widely distributed, even if we take it" in 

 the restricted sense as originally used by Logan and, later, by 

 Irving i, and leave out doubtful deposits which have been connected 

 with it- 



The Huronian marks a period of igneous disturbance and coarse 

 mechanical deposition succeeding to the Laurentian foldings. It is 

 essentially a coastal or marginal deposit, and indicates that at the 

 close of the Laurentian considerable areas of land had been elevated 

 in the northern hemisphere. It was along the margins of this old 

 Laurentian land that the Huronian was deposited, and its outcrops 

 mark these margins, which in America before the rise of the Appa- 

 lachians extended westward from the Atlantic coast along the 

 southern shores of the Laurentian land. The conditions of deposit 

 in Wales at the same period were evidently in general similar, though 

 with local peculiarities. 



Two important questions arise from the above statements. The 

 first relates to possible deep-sea deposits of this age, differing from 

 the coarse marginal detritus and volcanic accumulations. These 

 must have existed ; but to what an extent are they known to us ? 

 The limestones associated with the Huronian probably belong to 

 their margins ; but they have so far aff'orded no fossils except ob- 

 scure indications of sponge-spicules in the chert-nodules which they 



* Bailej-, " G-eology of New Brunswick," Geol. Survey Eeport 1877-8 ; Ells, 

 ' Histoi'y of New-Eruuswick Greology,' 1887. 

 t Geological Survey Eeports, 1878. 

 I Amer. Journal of Science, 1887. 



