LOWER CAMBRIAN TERRANE 319 



appear. The St. John quartzite was evidently formed from a 

 well-washed white quartzitic sand that was spread quickly and 

 evenly over the Lower Cambrian sediments. The currents of 

 water loaded with sand undoubtedly eroded to a slight degree 

 the subjacent Lower Cambrian deposits, but in the only section 

 where I saw the actual contact there was no evidence of this. 

 Mr. Matthew speaks of the great erosion of the Lower Cambrian 



* Etcheminian' prior to the deposition of the St. John quartzite, 

 citing as proof the absence of the Lower Cambrian beds beneath 

 the quartzite. It does not appear that he considered the possibility 

 that the Lower Cambrian sediments might never have been de- 

 posited over the areas he mentions, and that the Middle Cambrian 



* St. John' sediments covered the 'Etcheminian' and overlapped 

 on the Algonkian. Exactly the same conditions prevailed about 

 Trinity and Conception Bays, Newfoundland, where, with a 

 fixed datum line in the Smith Point (Hyolithes) limestone, we 

 found from 30 feet of strata in one locality to 400 feet in another 

 between the Hyolithes limestone and the subjacent Algonkian 

 rocks. At St. John, New Brunswick, the quartzite is close 

 down on the Algonkian. At Hanford Brook 1040 feet of Lower 

 Cambrian beds occur between them. Mr. Matthew's view is 

 that the 1040 feet of the Hanford Brook section were nearly and 

 in some places completely eroded off the St. John City area be- 

 fore the deposition of the Cambrian, not that they were never 

 deposited. 



In the St. John basin the strata are more or less disturbed and 

 tilted at angles varying from 10° to vertical. As usual under 

 such conditions, there is more or less displacement between the 

 massive unyielding stratum of quartzite and the softer more 

 yielding shales above and below. Even if there is no break a 

 decided difference in dip may occur only a few feet away from 

 the more unyielding stratum. The behavior of strata under 

 such conditions is beautifully shown at several points in the 

 Lower Cambrian of the Hanford Brook section. It is only on 

 the evidence of well exposed contacts (such as that at the head 

 of Seely street) that conformity or unconformity can be estab- 

 lished between the harder stratum and the more easily flexed 

 shales. 



