No. 1.] MATTHEW — GEOLOGY OP NEW BRUNSWICK. 105 



On its top are numerous fragments of coarse gray diorite and 

 hjpersthenite mingled with the red granite of the mountain, 

 "which must have been carried up a steep slope from ledges 500 

 feet below the summit. Westward of the hill there is a broad 

 gap in the range, to which the descent from the mountain top is 

 nearly as steep as it is on the north. Through this opening ice- 

 bergs would have found an easy passage to the low-lands south of 

 the hills without being compelled to ascend the mountain. 



The influence of the soft carboniferous shales upon the colour 

 of the Boulder and Champlain clays of the district to which the 

 fourth group of strire belongs, is even more noticeable than their 

 efiect upon that of the granite country. The four longitudinal 

 valleys which here terminate in the valley of the St. John river, 

 like the harbours to which I have alluded, ante-date the Carbon- 

 iferous age, and are occupied to a greater or less extent by Car- 

 boniferous strata. This is more especially the case at the upper 

 ends of the valleys, for at the lower ends, where they connect 

 with the valley of the St. John, denudation has swept away the 

 greater part of these deposits. In this way beds of soft slates 

 of the St. John group (Primordial) are usually revealed in the 

 valleys, the dividing ridges being in most cases hard rocks of the 

 Huronian and Laurentian systems. The slates of the St. John 

 group lying in these narrow valleys, while they have evidently 

 contributed to the formation of the surface clays, do not appear 

 to have deepened their colour materially, or caused them to ap- 

 proximate in tint to the gray clays of western Charlotte County. 

 In the large areas of red, gray and chocolate-coloured shales of 

 the Lower Carboniferous formation, about the upper ends of these 

 valleys, a continental glacier would find ample scope for extensive 

 erosion; hence it is not surprising that dark reddish-brown and 

 liver-brown shades should be found to prevail in the Leda or 

 Champlain clays about the city of St. John. 



Moraines.— The region over which the Unmodified Drift in 

 southern New Brunswick is spread, is to a great extent forest-clad, 

 and its surface features concealed from view. In the lower dis- 

 tricts which are cleared and settled, the drift has been greatly 

 disturbed by the play of strong ocean currents over the surface 

 of the land at the opening of the Champlain epoch. Ilcnce it 

 will be difiicult to determine how far the ridges of coarse mate- 

 rials, often many miles in length (denominated Horsebacks) are 

 old moraines, or to what extent they consist of accumulations in 



