MINERALOGICAL NOTES. 159 



eruptive dome-shaped bosses of the hornblende granite 

 areas of Saugus, Lynnfield, Peabody, Manchester and 



Cape Ann, there are numerous fragments and masses of 

 these metamorphosed crystalline sediments. At Saugus 

 on the east and at Lynnfield on the west of the granite 

 there are extensive outcrops which are seen to be inter- 

 stratified with layers of quartzite and mica schist. This 

 mica schist is identical, macroscopically and microscopic- 

 ally, with the metamorphosed argillites of Nahant and 

 Flying point, Marblehead neck. The strike of all these 

 beds is N. E. to S. W., varying only a few degrees 

 either to the north or east, thus showing that the intru- 

 sion of the eruptive magma was parallel to the foliation 

 of the sedimentary beds. On Cape Ann there are numer- 

 ous masses and fragments of the metamorphosed sediments 

 in the hornblende granite bosses. One large mass, near 

 the Loaf, a rocky point on the northern end of Coffin's 

 beach, on the western side of Cape Ann, at West Glouces- 

 ter, is several rods in extent and the foliation shows the 

 strike to be northeast to southwest. This outcrop is 

 below the high water line and therefore the dip could not 

 be well made out. Another outcrop on the east side of 

 Cape Ann, near Halibut point, is of the same type and 

 has the same strike, with the dip 40° west, parallel to the 

 Cambrian beds at Rowley and Nahant. The position of 

 these two metamorphosed crystalline sedimentary beds 

 signifies that they are remnants of an anticlinal fold of the 

 Cambrian sediments perhaps produced by the intrusion of 

 the eruptive granite magma from beneath them. It is 

 not unreasonable to presume that the granite magma melted 

 and enclosed large masses and fragments of these old 

 Cambrian sediments, metamorphosing them into horn- 

 blende and mica schists. This theory will also explain the 

 presence of several gneissic fragments found in the granite 

 quarries. One such, in the Trumble quarry in West Glou- 



