No. 8.J ACADIAN GEOLOGY. 473 



remarkable for its great development of trappean rocks, a large 

 space is devoted to the Carboniferous, and more especially to the 

 recognition of a Permo-Carboniferous or perhaps truly Permian 

 development of lied Sandstones in its upper part, containing a 

 peculiar flora in many respects resembling that of the European 

 Lower Permian. Details and figures are also given as to new 

 species of Batrachians, Fishes, Insects and Crustaceans recently 

 discovered, and a detailed analysis of the remarkable development 

 of the Lower Carboniferous or " Sub-Carboniferous " of American 

 Geologists, in comparison with that of other countries. 



After a short notice of the Devonian, which in the regions 

 referred to is chiefly remarkable for its rich flora, in the main 

 distinct from that of the Lower Carboniferous, and now number- 

 ing 125 described species, the author proceeds to discuss the 

 difficulties attending on the study of the Silurian and Cambrian 

 formations, in a region where they are much disturbed and 

 altered, and associated with igneous beds of very varied character. 

 On this subject he remarks : — 



" In the Acadian Provinces, as in some other parts of Eastern 

 America, the great igneous outbursts, evidenced by the masses 

 and dykes of granite which cut the Lower Devonian rocks, make 

 a strong line of distinction between the later and older Palaeozoic. 

 While the Carboniferous series is unaltered, except very locally, 

 and comparatively little disturbed, and confined to the lower 

 levels, the Upper Silurian, and all older series, have been folded 

 and disturbed and profoundly altered, and constitute the hilly 

 and broken parts of the country. Further, in the Upper Silu- 

 rian and the older periods, there seems to have been a constant 

 mixture with the aqueous -sediments in process of deposition of 

 both acidic and basic volcanic matter, in the form of ashes and 

 fragments, as well as probably outflows of trachyte and dioritic 

 rock, so that all these older formations are characterized by the 

 presence of felsite and porphyry and petrosiliceous breccia, and 

 of diorite. Further, since these volcanic and tufaceous rocks, 

 owing to their composition, are much more liable to be rendered 

 crystalline by metamorphism than the ordinary aqueous sedi- 

 ments from which the bases have been leached out by water, and 

 since they are usually not fossiliferous, the appearance is pre- 

 sented of crystalline non-fossiliferous rocks alternating with others 

 holding abundant organic remains, and comparatively unaltered. 



