140 



MATTHEW ON CAMBEIAN 



exposure of the relations of this series to thé St. John group, and has afforded some fossils 

 which help to fix the age of the Basal series. Unfortunately faults occur at the contact of 

 this series Avith the St. John group, so that the first layers of the latter are not visible, but 

 the relation of the one series to the other is unmistakable. 



Fig. 2. 



S 'John Group 



:\> ■:-^'-;^4y 



»lVo.m B..rte«iV Spon<)ft^„ fcn-,a.as I P!^ljS^Ur^^t',a > 



Sketch Map of Caton'$ Island (*oo/«//oij« i«MJ and Seclions of hs 

 Cambrian rocks joo/tet to an im/i). 



A sketch map of the island with two sections across it will serve to make clearer the 

 relations of the different members of the Cambrian system that occur there, and the 

 horizons at which the fossils are found. In this map the unshaded portion of the island 

 is occupied by the Basal series, and the shaded part by the St. John group, of which 

 only Divisions 1 and 2 are found on the island. The upper section taken on the eastern 

 side of the island (lower side of the map) shows only the St. John group, Avhich is divided 

 into two portions by an area where the measures are concealed. The lower section was 

 taken on the western side of the island (upper side of the map), and shows the Basal 

 series, with a small portion of the St. John group at the northern end, divided off by a 

 fault. Band a of Division 1 of the St. John group does not appear anywhere on this 

 island, but at a point about seven miles south-west of this island, on the north side of St. 

 John River it is found at the contact of the two series, being a baud of grey sandstone 

 about twenty feet thick. 



I have remarked above that the Basal series affords indications of the fauna Avhich 

 accompanies the trilobite genus Oleuellus and its kindred genus Mesonacis,' but indica- 

 tions of a similar fauna are also found in the two lowest bands of the St. John group. 

 A few words, therefore, on the organisms of these bands in support of the parallellism 

 suggested in the preceding table may with advantage be added here. 



There is in all the Cambrian basins in this province, just below the oldest beds 

 which are known to hold Paradoxides, a bed of shales of considerable thickness (\b, 5), 

 which though apparently no coarser or more siliceous than the beds below, stands ox\t in 

 the sections with peculiar massiveness. It contains some fragments of trilobites, many 

 Dictyonine sponges and other low organisms, and the brachiopods lie entombed in it at 



' See note at the end of this article in reference to Mesonacis and Holmia. 



