58 



of succession in the crystallization, seeing that the various 

 minerals enclose and penetrate one another. The lepido- 

 melane, however, has a much better form than the other 

 constituents and would thus seem to have crystallized 

 earlier. 



An analysis of the biotite-bearing variety is given on 

 page 96. This nepheline syenite in the quantitative 

 classification ranks as an essexose. It contains 3-45 per 

 cent of calcite. 



The road then passes further in toward the centre of 

 the intrusion, affording excellent exposures of the red 

 syenite described on page 55. Near Hotspur Corners the 

 relation of the syenite and the nepheline on the western 

 side of the mass will be seen. 



Leaving this interesting intrusive mass, the road then 

 continues in a westerly direction over limestone penetrated 

 in one place by a small intrusion of granite to another 

 intrusion of nepheline syenite and allied rocks, which is 

 of interest. 



Nepheline syenite intrusion in the western part 

 of the Township of Monmouth. 



This occurs on lots 9, 10 and 1 1 of ranges VII and VIII 

 of the Township of Monmouth. It is a lenticular mass 

 approximately one mile (i-6 km.) long and 700 yards 

 (640 m.) across at its greatest width and is formed of a 

 body of nepheline-bearing rock presenting an example of 

 extreme differentiation. As usual in this district, these 

 rocks have a marked foliation and are developed as a 

 series of schlieren rudely parallel to one another and 

 conforming to the strike of the enclosing limestone. Some 

 of the schlieren are highly feldspathic varieties of nepheline 

 syenite, but others contain little or no feldspar. Others 

 are composed almost exclusively of nepheline, while still 

 others consist essentially of nepheline and ferromagnesian 

 constituents. 



The following three varieties have been carefully 

 studied: 



(1) Nepheline syenite (1st variety). 



This variety is coarse in grain, dark in colour and rich 

 in hornblende. Under the microscope it is seen to consist 

 of nepheline, albite, hornblende and calcite, with a small 



