GEOLOGICAL AND MINERALOGICAL NOTES: NO. 5. 9 



desertecl quarries, and one especially good section of this 

 Syenite is seen hy tlie roadside opposite Yoiing Avenue, 

 Lanesville. The trend or strike of all of the outcrops is 

 in the usual direction, N.N.E. to S.W. 



This entire outcrop is some twelve miles long and 

 froni a few rods wide in Hamilton to six miles in Essex 

 and Manchester, the latter width continiüng across Glouces- 

 ter from Lanesville to Eastern Point. 



This rock has been recorded as granite by the earlier 

 authors and as granitite by more recent ones. A large 

 part of the granite area mapped by Professor W. O. Crosby 

 in Hamilton, East Wenham, Essex, Manchester and West 

 Gk)ucester is this typical augite-syenite. Speciniens of 

 this rock, which I collected near the terminus of the Essex 

 branch railroad in 1887, were determined by Prof. W. O. 

 Crosby as one of the members of the syenite group, and 

 at that time he advised a careful examination of the rocks 

 of the whole region, which has been done with the above 

 results. 



The determinations of the minerals in this rock, studied in thin sec- 

 tions with the polarizing microscope, are as follows : — Orthoclase, 

 brown hornbleude, red mica (probably phlogophite) , mucli titanite, 

 numerous fine sections of augite, several small crystals of apatite, a 

 few small zircons, one section of microcline in one of the slides, Ba- 

 veno t\^in crystals of orthoclase which show the intergrowth of al- 

 bite as microperthite The augite is often surrounded by magnetite, 

 and di.st-like inclusions of magnetite in the orthoclase give this syenite 

 its darkcolor. In some of the sections from the outcrop at Prospect 

 St., Gloucester, there are some quartz blebs, but the rock as a whole is 

 poor in quartz and resembles the Syenites of Charnwood, England, de- 

 scribed by Prof. T. G. Bonney and ßev. Edw. Hill (Quart. Jour. Geol. 

 Soc. Vol. 34, 1887, p. 215). 



(B), Granophyre (H. Rosenbnsch) : Granulite. Oc- 

 cupyingthe regi(m betvveen Freshwater Cove ViUage and 

 the West Gloucester raib'oad Station, and extending in a 



ESSEX INST. BULLETIN, VOL. XXV 2 



