REPORT OF THE DIRECTOR AND STATE GEOLOGIST 1900 r95 



In this coimection, it should be noted further that the plane 

 differentiation exhibited by the syenite here at Little Falls would 

 seem to afford coTroborative evidence of the truth of the view 

 advanced in the preceding report, when considering the general 

 relationships of the great eruptive matsses of the Adirondacks. 

 The small eruptive mass at Little Falls shows variation to gran^ 

 ite and to gabbro as the two extremes. The rather basic augite 

 syenite dikes described as cutting the anorthosite at various 

 places, in the preceding report, and which were inferred to be 

 offshoots from the main syenite intrusion and to indicate the 

 younger age of that intrusion, are in all respects like some of the 

 more basic phases of the Little Falls rock, where they appear as 

 unquestionable variations of the syenite. There is also sug- 

 gested the further query, whether some of the Adirondack gab- 

 bro should not also be classed as of the age of the syenite and 

 as a direct derivative from it. There is certainly gabbro of such 

 origin at Little Falls, and may well be elsewhere. 



Structural notes 



Most of the rock at Little Falls is sufficiently well foliated to 

 permit satisfactory dip and strike obsieirvations. At the village 

 the foliation planes strike east and west, with dip 15 s.; ^ mile 

 farther east the strike is n. 60 w. and dip 20 n. ; -J mile farther the 

 strike has swerved back east and west^ and near the fault line 

 it is n. 80 w. 



At the village the main pair of joints are vertical and trend to 

 n. 20 e. and n. 50 w.; 1 mile to the east, readings of n. 30 e. and 

 n. 60 w. were obtained on the same pair. These joints vary but 

 little in direction thronghont the exposures, follow one another 

 at distances of from 1 to 3 feet, and are very evenly and 

 sharply cut. Often also good horizontal jointing appears, and 

 there seems to be another vertical set bisecting the angles of 

 the first, but much less well marked. 



