20 Report of the State Geologist. 



the rock is well foliated. The more strongly acid gneisses are well jointed, the 

 ordinary gneiss lacking this structure ; the former may represent the later 

 granites, decisive evidence on this point not having been found. The pyroxene 

 gneisses, which are such a feature in Malone and Belmont, are mainly lacking 

 here, though they are present to some extent. Considerable gabbro-diorite 

 gneiss occurs together with the usual dikes of hornblende gneiss. Near the 

 west line of the township are widespread exposures of acid granitoid gneisses, 

 which alternate with masses of gabbro-diorite gneiss of considerable thickness. 

 The two blend into each other along their contacts. 



The Potsdam sandstone makes but meagre showing in these townships, 

 the drift being very heavy. In the stream at South Bangor there are slight ex- 

 posures of a buff, hard, coarse sandstone. There is an old quarry on the 

 Bangor-Brandon line from which a slight amount of stone has been taken, the 

 rock here being white and not well indurated. One mile to the south-west the 

 red, hematitic arkose of the basal portion of the formation is poorly exposed 

 by the roadside only a few yards away from the gneisses. This was the only 

 outcrop lying close to the boundary observed in the township. 



Dickinson. 



In this township the boundary trends to the south-west. In the 

 north-eastern corner the gneisses are well exposed at the end of a low 

 ridge with Potsdam sandstone close at hand to the north. The entire western 

 flank of the ridge is, however, so thoroughly drift-covered that no exposures 

 are to be found until those opened by the Deer river are reached, so that 

 the boundary here is uncertain though the topography indicates a position 

 approximately as shown on the ma}). At Dickinson Centre and thence west- 

 ward to the county line and beyond, outcrops of gneiss are plentiful with, in 

 one case, the Potsdam in place only a few yards away. 



The gneisses in the north-eastern part of the township are for the most 

 part red, acid gneisses of microcline or microperthite and quartz, often coarse and 

 full of (piartz and pegmatite veins, as is usual in these gneisses. With these 

 are narrow, sharply defined basic bands of hornblende gneiss which constitute 

 but an insignificant proportion of the whole. 



Around Dickinson Centre and for a mile and a half eastward, the rock is 

 largely gabbro-diorite gneiss. This grades on the one hand into hornblende 

 gneiss ( < 1 i< n-ite gneiss) and on the other into a red orthoclase gneiss which 

 carries the same aegerine-augite and deep orange titanite which are found in 

 the gabbro-diorite. This in turn gradually shades into the ordinary red 



