8 L. W. BAILEY : 



iiecliou with the areas referred to this horizon arises from the fiudiug, at difFerent points 

 within the latter, of fossils which indicate a more recent origin than that assigned to the 

 larger districts in which they occur. Thns, in the very heart of the supposed Cambro- 

 Silurian band, in York County, a narrow belt containing forms of transitional character 

 between the Silurian and Devonian, was found as early as 18*79, by the late Chas. Robb ; 

 and quite recently still other forms, somewhat obscure but apparently Devonian, have 

 been discovered, by Mr. W. T. II. Reed of Fredericton, in the slates a few miles north of 

 that city. It may thus eventually prove to be the case that within the area ascribed to 

 the Cambro-Silurian, there are considerable tracts of younger strata, either Silurian or 

 Devonian, or both ; but the fact that on the north side of the central granite belt the slates 

 in question are so obviovisly and at so many points met and overlapped by undoubted 

 Silurian strata, taken with the known occurrence of Lower Silurian forms on the 

 Beccaguimic, and of graptolitic slates which are probably Lower Silurian, in the eastern 

 extension of the same belt, near Bathurst, would seem to be sufficient reason for continu- 

 ing for the present to assign this age to the group in question. It may be added that 

 rocks very nearly resembling many of those which have in New Brunswick been regarded 

 as Lower Silurian, have recently been observed by the writer in northern Maine, where 

 they would seem to be unconformably covered by Silurian conglomerates, made up of 

 their debris ; but the determination of the exact age of all these slaty rocks in both 

 countries, is among the most important problems in the geology of this region still 

 requiring solution. 



I may add that the same uncertainty rests upon the age of the so-called Kingston 

 G-roup, of southern New Briiuswick, and which in its westward extension becomes, in 

 part at least, continuous with that to which Prof. Shaler has assigned the name of " the 

 Campo Bello Series." By that author, who assigns to strata of the group a thickness of 

 at least 4,000 feet, and compares them with the slates of the Cambridge district in Massa- 

 chusetts, they are regarded as being Lower Cambrian ; but as beds of very similar charac- 

 ter occur within a very short distance of the known Cambrian of St. John, and yet bear 

 but little resemblance to the latter, this supposition seems untenable. As they are certainly 

 older than Silurian, and in all probability not Cambrian, they must either be regarded 

 as Pre-Cambrian, the view adopted in the Survey reports, or as Cambro-Silurian. 



«The rocks of the Silurian system are among the most widely spread and most in- 

 teresting of those found within the district to which this paper relates. No other forma- 

 tion has determined so large an extent of arable land ; none is more remarkable for its 

 physical features, whether of mountains, lakes or rivers, and over none is the distribution 

 of native plants more peculiar. Within it are included the Aroostook region, so well 

 known for its fertility, in northern Maine, and a corresponding " fertile belt" in northern 

 New Brunswick ; and it was long since pointed out, by Prof G-. L. Groodale, that many of 

 the species of plants here met with are such as naturally belong to a more southern 

 parallel. Finally, the formation is the first one in which is indicated anything like a 

 definite idea of the early geography of this portion of America. 



Although the general age and distribution of the larger part of the rocks referred to 

 this system has been long known, it is only quite recently that any attempt has been 

 made, so far as New Brunswick is concerned, to effect any svibdivision of the latter or to 

 determine the relation or equivalency of its different portions. Indeed, this could not 



