[ells] CAMBRIAN ROCKS OF SOUTHERN NEW BRUNSWICK 119 



(Cambrian) as at Métis and elsewhere, from which Hexactinellid 

 sponges were obtained some years ago, and described by Sir William 

 Dawson in a paper read before this Society in 1889. Some of these 

 forms from the Cambrian of Quebec appear to be almost identical 

 in character with those from the beds about St. John; but nowhere in 

 Canada or elsewhere, in so far as known have they been obtained from 

 rocks of lower horizons than the basal Cambrian; the species known 

 as Archaeocyathus, found in Newfoundland many years ago, and 

 doubtfully referred to the upper Huronian or lower Cambrian being 

 the oldest known form yet recorded. The exact nature of this organ- 

 ism, whether a coral or a sponge, is still somewhat uncertain. It is 

 generally regarded, however, as representing the lowest known re- 

 presentative of the sponges. 



To separate these low forms found in the St. John rocks from 

 other low types of sponges obtained from the Etcheminian division 

 of that city by some 20,000 feet or more of Huronian rocks is a problem 

 requiring careful consideration ; since if the former determinations 

 of horizons are to be taken as correct, it would imply an enormous 

 interval of time with but little change in the character of the organ- 

 isms which occur in the middle and lower Cambrian and those from 

 the so-called upper Laurentian of this area. 



Summing up the present evidence bearing on the question, it 

 would seem that the portion of these St. John rocks, formerly assigned 

 to the horizon of the upper Laurentian, is more closely related to the 

 recognized middle and lower Cambrian, both as regards their physical 

 character, their stratigraphical sequence and their contained fossils, 

 than to any other series of formations found in the area about that 

 city. It may be mentioned in this connection that in the list of 

 organisms published by Dr. Matthew as occurring in the Etcheminian 

 portion of the Cambrian (Bull. Nat. Hist. Soc. Vol. X) a number of 

 forms are given, including several varieties of Archaeocyathus such 

 as pavenoides, elegans, elongata, virguloides, all of which are referred 

 to Div. C. of the St. John group with remains of Protospongia ; while 

 several forms including Dichoplectella, Hyalostelia, and Plotoscyphia, 

 are referred to the horizon of the Etcheminian or lowest division of 

 the Cambrian. The forms Cyathospongia and Halichondrites, found 

 in the supposed upper Laurentian of St. John, are given in Sir William 

 Dawson's list as occurring in the Sillery division of the Quebec group 

 (Cambrian) at Metis. 



Another point of considerable interest in connection with the 

 lowest hitherto recognized beds of the Cambrian of southern New 

 Brunswick, is the apparent absence in all the sections made in the 

 several areas about St. John city and eastward to Handford brook, 



