PART II 



PAL^EONTOLOG-Y. 



In consequence of the finding of trilobites, Brachiopods, etc., and of 

 Cambrian genera in the Etcheminian strata, and for reasons given below, 

 the writer proposes to revert to the classification of 1889, wherein these 

 deposits are called the Basal Series (of the Cambrian System).* 



It has been found that slates with fossils of Cambrian genera are Volcanic 



. rocks at the 



included in the important group of volcanic rocks which lie at the base of the 



base of the Etcheminian, and that where the dip of the volcanics can be 

 found, as is not infrequently the case, it agrees with that of the Etche- 

 minian. It is thought therefore that those volcanics (the Coldbrook 

 group) should be included in the Basal Cambrian. 



Both in New Brunswick and in Cape Breton the Coldbrook group 

 begins with lavas showing deposition free of pressure, as they are amyg- 

 daloidal ; or with agglomerates devoid of evidence of marked aqueous 

 wear. The deposition therefore did not begin in deep water, or on 

 exposed sea coasts, or under heavy pressure. The foundation upon which 

 the volcanics rest shows in several places marks of deep sub-aerial decay 

 at the line of contact. Calcareous bands are dissolved, leaving the 

 silicious portion of the strata. The feldspar of the granitic rocks is Worn condi- 

 kaolinized, and the magnesian silicates are hydrated, impure graphite p 

 beds are changed to a black amorphous crumbling shale, and a depression sediments. 

 or narrow valley is usually found at the contact of the two terranes. 

 These conditions appear .to indicate that the pre-Cambrian complex had 

 long been above the sea-level in these districts when the first Cambrian 

 effusives were thrown out upon it. 



Another point worthy of note in this connection is the large amount 

 of feldspathic material in the Etcheminian beds ; the very sands are often 

 composed of feldspathic grains, and these largely of non-kaolinized feldspar, 

 as though they had not been exposed to sub-aerial decay. Feldspar in 

 this condition is found in two kinds of deposits, those that are the result 



* Trans. Roy. Soc. Can., vol, vii, Sec. iv. p. 135. 

 5 C. K. 



