Skction IV., 1904 [ 123 ] ^ Tkans. R. S. C. 



* 



V. — The Volcanic EocTcs of New Brims ici cl: 

 By L. W. Bailey, LL.D. 



(Read June 22, 1904.) 



Tn reviewing the fccitures of the geological formations to be found 

 in New Brunswick^ an observer cannot but be struck by the frequency 

 with which rocks of igneous or semi-igneous origin are brought to one's 

 notice, as in the iield he is equally surprised at the extent of the areas 

 which they occupy. , Being thus met with in systems of widely different 

 age and with veiy unlike association, a wide field of comparative study 

 is opened, upon which as yet but few observers have entered. It is for 

 the purpose of stimulating inquiry in this direction, and possibly of 

 affording some assistance in its prosecution, that the following paper 

 Jias been written. 



The geological column in New Brunswick embraces rocks referable 

 to Pre-Cambrian, Cambrian, Ordovician, Silurian, Devonian, Lower 

 Carbondferous, Carhoniferous and Triassic horizons, and of these one 

 only, viz., the Carboniferous or Coal Measures, lacks evidences of 

 volcanic intrusions, while the Huronian of the Pre-Cambrian systems, 

 the Silurian, the Lower Carboniferous and the Trias are those in which 

 suet evidences are most widespread and most conspicuous. In noting 

 the^'-^ varying characteristics and associations we may pursue an ascend- 

 ing order. 



Laurentian . 



The only rocks which upon definite evidence have been referred to 

 this horizon are confined to the southern counties of St. John and Kings, 

 where they consist for the most part of gneisses, quartzites and lirac- 

 stoDjes, associated with granite and syenite. Though the latter are pro- 

 bably intrusive, and cover considerable tracks, they do not fall within 

 the group which it is proposed to consider here. But quite apart from 

 these the rocks of this system are found to be penetrated by innumer- 

 able dykes of what was evidently at one time melted rock, and the in- 

 fluence of whose fusion can be clearly seen in the alteration of the strata 

 thrcmgb which they passed. Admirable opportunities for the study of 

 these dvkcs is to be found in the numerous quarries opened in the 

 vicinity of the city of St. John for the removal of limestone, where the 

 marked contrast of colour between the gray or sometimes nearly white 

 limestone with the dark greenish gray or black colour of the effupive 



Sec, IV., loot. 



