CAEBONIFEROUS UNDIVIDED. 383 



L 19-20. NEW BRUNSWICK. 



The Carboniferous of New Brunswick comprises Mississippian, Pennsylvanian, 

 and Permian strata. They have been studied in detail and have been the sub- 

 ject of several reports and discussions. BaUey^^^ has recently summed up the 

 general facts in an article from which the following extract is taken. 



In the reports and maps of the Geological Survey it has been usual to regard this system 

 in New Brunswick as embracing three principal members, somewhat strongly contrasted in 

 lithological characters and conditions of origin, viz, the Lower Carboniferous, the Carboniferous 

 proper or Coal Measures, and the newer or Permo-Carboniferous, the first consisting of reddish 

 sediments, with evidences of a generally marine origin; the second mostly gray or purplish, 

 rarely red beds of marsh or fresh- water origin; and ,the third again showing a predominance of 

 red tints, though without the marine limestones, gypsums, and salines which distinguish the 

 Lower Carboniferous formation. In the "Acadian geology" of Sir William Dawson (1868) the 

 Carboniferous proper was further subdivided into the "Millstone grit series" and the "Middle 

 coal formation;" while with the marine limestones of the Lower Carboniferous division were 

 associated, under the name of Lower Coal Measures (in addition to some beds resembling the 

 Middle Coal Measures) the bituminous deposits known as the Albert shales. 



It has already been stated as regards the peculiar shales last mentioned that there is at 

 present a growing tendency to regard them as of Devonian rather than Carboniferous age, 

 bemg the equivalents of the fish-bearing and fern-bearing rocks of the Bale des Chaleurs, though 

 very unlike them in their physical aspects. It has also been stated that there are serious objec- 

 tions to this view; but as the question is mainly one of the interpretation of fossils and has little 

 or no bearing upon the main subject of this report, that of the true coal-bearing rocks, it need 

 not be further considered here. The doubtful beds in question being thus eliminated, the rocks 

 which lie above them are very easily and clearly divisible into two great groups, viz, the Lower 

 Carboniferous formation and the Carboniferous proper, or Coal Measures, while another, viz, 

 the Upper or Permo-Carboniferous is less certainly distinguishable. The characters of these 

 several subdivisions may be briefly summarized as follows : 



Lower Carboniferous. — The lowest beds of tliis formation, as here limited, are usually coarse 

 conglomerates, their composition and hence their general appearance varying with the nature 

 of the rocks upon which they rest. They are, however, in almost every instance of a reddish 

 color, varying from a clear rich red to a dark brownish red. They are usually also much harder 

 than similar beds higher in the series, and in places are much stained with oxide of manganese. 

 The cement is always to some extent and often very markedly calcareous. At some points, as 

 at Quaco Head, St. John County, similar conglomerates are underlain by beds of limestone, 

 but the principal limestone strata are situated at the summit rather than at the base of the 

 formation. The conglomerates are usually followed by or interstratified with sandstones, also 

 usually of a reddish color and markedly calcareous. Higher still the beds become finer, embrac- 

 ing shaly and marly deposits, upon which in many instances rest beds of gray flaggy, sometimes 

 bituminous limestone and heavy beds of gypsum. Between these higher beds and the basal rocks 

 of the coal formation (Millstone grit) it is common to find extensive sheets of igneous rocks, some- 

 times in the form of compact diabase, sometimes as a vesicular or amygdaloidal ash rock, and 

 sometimes as claystone or rhyolite; but such plutonic masses are not confined to the summit of 

 the formation, being sometimes, as at Quaco, near its base. Where igneous rocks are associated, 

 as at Quaco and Hampstead, Queens Coimty, with limestones, the latter have been more or 

 less completely converted into marble. 



The thickness of the Lower Carboniferous system varies greatly, but, according to meas- 

 urements made by Dr. E. W. Ells in Albert and Westmorland, it reaches in those counties about 

 5,000 feet. Its thickness in the central basin is probably much less. [For "Coal Measures," 

 see Chapter X, p. 473; for "Permo-Carboniferous" see Chapter XI, p. 498.] 



