LOWER CAMBRIAN TERRANE 339 



Ordovician, Silurian, etc. It appears to be inapplicable for such 

 use, as it is equivalent to Georgian. For the Lower Cambrian 

 formation on Hanford Brook the best name is Hanford, as that is 

 the typical locality where the terrane may be studied. It was 

 applied to the formation in 1891.^ For the Lower Cambrian of 

 Newfoundland the local name Placentia was used in 1891. In 

 1889 Terra Nova was used in the same sense as Mr. Matthew 

 uses Etcheminian.^ Both names are unnecessary, as Georgian 

 includes all the Lower Cambrian terranes and formations. 



The term St. John should be limited to a definite formation 

 or group of formations. We now have the St. John quartzite, St. 

 John shales and St. John group. It has long been applied to the 

 St. John terrane, and I think should be used in the broad sense. 

 If this is done the basal quartzite should receive a local name, 

 as well as the shales above. The quartzite might be called the 

 Seely quartzite, from the fine exposure on Seely street in the 

 city of St. John, and the shales the Ratcliff formation, from the 

 typical locality on Ratcliff's mill stream. 



Conclusions. 



(a) The ' Etcheminian ' terrane of Matthew is of Lower 

 Cambrian age. 



(3) The Olenellus fauna is older than the Paradoxides and 

 Protolenus faunas of the Middle Cambrian. 



{c) The Cambrian section of the Atlantic Province'"* of North 

 America includes the Lower, Middle, and Upper Cambrian di- 

 visions as defined by me in 1891. 



Bull. U. S. Geol. Survey, No. 81, p. 360. 



»Amer. Jour. Sci., 3d ser., Vol. XXXVII, p. 383. 



"I do not think it is necessary to discuss the Cambrian rocks of Massachusetts. 

 Once the typical ' Etcheminian ' is shown to be of Lower Cambrian age, all 

 correlated formations go with it. 



