258 ON THE GEOLOGY OF ST. JOHN. 



of Albert, which according to Dawson are beneath the carbon- 

 iferous conglomerates of that county. 



The Carboniferous strata both in the valley of the Kennebecka- 

 sis and on the coast have been crumpled up in the same manner 

 as the Devonian of the intervening district, but at a later epoch. 

 In the small deposit of New-Red-Sandstone at Gardner's Creek,, 

 these plications do not occur. 



General Remarks. — In reviewing the general features of the 

 deposits which I have attempted to describe, the rarity of deep 

 water accumulations is worthy of note. Above the limestones of 

 the Portland series the strata consist almost entirely of littoral 

 or subserial deposits ; the finer shales of the St. John group and 

 some limestones at Black river being the only beds which indicate 

 a deep water origin. Ripple-marks, and other evidences of a sea- 

 margin bave been observed at three different levels in the St. 

 John slates, and also at several places in beds of the Little River 

 group and as already stated rain marks also occur. 



The evidences of volcanic activity during the period marked by 

 the Coldbrook beds, and the great accumulations of lava, ashes,, 

 and volcanic mud, which form the bulk of the Bloomsbury group,, 

 as well as the proof of renewed igneous action met with among 

 the vast beds of gravel, sand, and clay subsequently formed, show 

 that in some points the circumstances which attended the forma- 

 tion of Devonian deposits in eastern America differed widely 

 from those which prevailed at the west. 



The source of the detritus out of which the Devonian beds at 

 St. John have been formed has not yet been ascertained ; but 

 that it is to be sought for in an easterly direction is obvious, since 

 all the deposits (except perhaps the highest) increase in bulk and 

 coarseness of material when traced in that direction. Its origin 

 is probably closely connected with that of the volcanic beds, which 

 as I have already shown are largely developed to the eastward. 



An intimate relation between volcanic deposits and red sedi- 

 ments seems to exist in these beds, the latter appearing to be a 

 consequence of the former. Thus red shales sandstones and con- 

 glomerates succeed the lowest member of the Coldbrook group ; 

 and a similar succession on a larger scale occurs in the Blooms- 

 bury beds. If I am correct in referring the metamorphic strata 

 of Black river to the cordaite shales or Mispeck group, a similar 

 succession appears in the higher beds, not vertically, however, but 

 horizontally. 



