212 



\\ . S. BAYLEY — SYENITES FROM NEW ENGLAND. 



From this we calculate that the ingredients are intermingled in the 

 proportions shown below : 



viz: 7 per cent of lepidomelane, 2 per cent of cancrinite, 17 per cent of 

 eleolite, 27 per cent of orthoclase (and microcline), and 47 per cent of 

 all lite. As was indicated by the microscopic study, no plagioclase other 

 than albite is present, and this, as is seen, is largely in excess of the 

 orthoclase. 



The rock, then, while certainly to be classed with the eleolite-syenites, 

 is nevertheless very unlike those that have been described from other local- 

 ities. It consists essentially of lepidomelane, eleolite and albite among 

 its undoubted primary components, and of orthoclase, albite, cancrinite 

 and sodalite among those of probable secondary origin. Even though 

 the orthoclase should he regarded as primary, it is not in sufficient quan- 

 tity to affect to any considerable degree the character of the rock. Its 

 structure is seen to be thoroughly granitic where the deformation pro- 

 duced by pressure is not so great as to obscure all traces of its original 

 character. Although, according to Rosenbusch's scheme, its composition 

 would carry the rook among the theralites, its characteristics certainly 

 point to the eleolite-syenites as its nearest relatives. The sodalite and 

 cancrinite of the eleolite-syenites are abundant in the Maine rock and the 

 dark color that is to be expected in the more basic plagioclase-eleolite 

 rock is lacking. The plagioclase of the former is the most acid one known. 



