iBAiLEY-MATTHEw] NEW BRUNSWICK GEOLOGY 123 



Still further evidence of the Pre-Carboniferous age of the Plant 

 beds at St. John is to be derived from a comparison of the latter-as to 

 nature, color, attitude, etc., with the rocks of Perry, Lower Carboni- 

 ferous, and higher groups. 



Another considerable area of Pre-Carboniferous rocks requires 

 brief notice in this connection. It is that of the area which, north 

 of the great Nerepis granite batholith, lies between the latter 

 and the southern margin of the central coal-field. The rocks here 

 are mainly argillites, but have been divided into two groups, known 

 respectively as the "dark" and "pale" argillites. The age of both 

 is still problematical. In neither have any determinable fossils been 

 found, but in the upper or paler series occur indistinct traces of 

 plants recalling those of the Little River group, and for this reason 

 they were, in the Geological Survey map, represented as Devonian; 

 while the lower dark argillites, which are often flinty and more or less 

 altered by granitic contact, were compared with the Mascarene 

 (Silurian) deposits of Passamaquoddy Bay. Should the plant re- 

 mains of the argillites prove to be the same as those of the Cordaite 

 shales, the fact would aff'ord further evidence that these latter are 

 Pre-Carboniferous. 



The Devono-Carboniferous or Perry Group 



This series of strata is readily distinguished from all below by 

 the condition of the cementing paste in the coarser beds, as well as 

 their evident superposition. This paste is not slaty, and, when 

 exposed to the weather, the lime in it is usually sufficient to cause the 

 rock to crumble. 



The greater part of the lowest beds of this series is of a dull red 

 color in the district around St. John, owing to the red color of the 

 clay of the paste. Here also there has been high land at the opening 

 of the stage, probably with ice tearing off and rolling down blocks of 

 Pre-Cambrian limestone from exposed ridges such as now lie between 

 the Bay of Fundy and the Kennebecasis river. At other points, as 

 on the Hammond River in Upham and again in Westmoreland county, 

 their appearance has been almost wholly determined by that of the 

 pebbles (granite, etc.) composing them, a resemblance so strong that 

 only a close view reveals their clastic origin. 



Plant remains are rare in the part of the series near St. John, 

 but at Perry, in Maine, just across the Canadian border, there are 

 plant remains at two horizons, and in these beds, which are chiefly 

 gray sandstones, is contained the Devonian flora which has made 

 the Perry rocks famous. This flora was first studied by Sir J. W. 



