GEOLOGY OF THE LONG LAKE QUADRANGLE 485 



In the Moose creek belt the dips are so flat that they can seldom be 

 made out with certainty. Elsewhere theV are higher, and in a few 

 instances distinct folds are shown. These are of the sharply pinched, 

 or closed type, steep south dips becoming vertical and then steep 

 north. But north dips are exceptional. Such folds as show pitch 

 show it to the west or northwest, but it can seldom be made out. 



Since no aid could be obtained from the stratigraphy in decipher- 

 ing the structure of the region, it was hoped that some light would 

 be thrown on it by a careful plotting on the map of all the observa- 

 tions on the foliation dip and strike [see map]. In many of the ex- 

 posures only the strike can be made out, and this is notably the 

 case in the poorly foliated erupti^es. Even in the gneisses the 

 foliation is often poor and indistinct, making exact observations 

 difficult, and the whole result is indecisive and disappointing. 



Taking the quadrangle as a whole, nearly east and west strikes 

 prevail, and the prevalent dip is southward. This either indicates 

 comparatively little folding, or else isoclinal folding, or else that the 

 foliation does not coincide with the bedding and so does not bring 

 out the folding. It is not possible to demonstrate which of these 

 alternatives is the true one, though the second is very unlikely, 

 and all the direct evidence obtainable is against the third. The 

 south dips vary widely in amount, and there is certainly considerable 

 local folding. In spite of the uncertain nature of the result, certain 

 facts are brought out. 



The foliation is more erratic in the eruptives than in the gneisses 

 and Grenville rocks. 



In the southeast the prevalence of east and west strikes and south 

 dips is noteworthy. In the southwest the strike has swerved to an 

 average n. 65° w. direction, the dip remaining south. Meridional 

 strikes are exceptional and most frequent in the central portion of 

 the quadrangle. Locally, on the northwest, north dips prevail. 

 There is a local prevalence of northeast strikes about the foot of 

 Long lake. The general nonfoliated character of the anorthosite is 

 brought out by the absence of observations in the territory occu- 

 pied by that rock. 



It is obvious that these observations must be extended over a 

 wider area before their significance can be apprehended. 



Joints. The number of readings taken on joints within the 

 quadrangle limits is 647. When tabulated in respect to direction 

 (all odd degree readings being reduced to the nearest 5° direction) 



