PENNSYLVANIAN ROCKS 449 



extends southward through Woonsocket, as noted by Emerson and Perry. 

 The conglomerates of the Bellingham series in Woonsocket are of very 

 coarse white qnartzite pebbles "mashed to rods and plates 12 to 14 inches 

 long." ^° A similar conglomerate is exposed near the town of Crooks 

 Corners (one mile west of Mechanicsville). Here the conglomerate con- 

 sists of qnartzite and Milford granite pebbles varying in length from an 

 inch to a foot, all greatly sheared and mashed, the elongation of the peb- 

 bles being in a north-sonth direction. Pebbles 1 foot in length have a 

 diameter of 3 inches. They are cemented by a light green paste. Else- 

 where, as west of Crooks Corners, the green conglomerate is exposed in 

 contact with schist. Often films of biotite have been developed along the 

 shearing planes and on the sides of the platelike pebbles. The latter con- 

 sist principally of white qnartzite and green schist derived from the 

 Blackstone series near by. In some of the sheared material the pebbles 

 are one-fourth of an inch thick and 2 inches long or one- third of an inch 

 thick and 3 inches long. 



The schist of the Bellingham series is dark green, massive, and fine 

 grained. It is exposed in two railroad cuts, one a mile west of Wads- 

 worth and the other west of Crooks Corners, at the margin of the Frank- 

 lin sheet. In thin-sections it is seen to consist of muscovite, quartz, 

 chlorite, and zoisite, with some magnetite. 



The Bellingham green schist can be distinguished from the green 

 schists of the Blackstone series by its freshness, lack of alteration, and 

 absence of epidote nodules. It is also more massive than the Ashton 

 schists. Its relation to the latter must be an unconformity, but out- 

 crops are so scarce in this drift-covered area that the contact of the two 

 series can not be accurately drawn. 



The age of the Bellingham series is supposed to be the same as that of 

 the JSTarragansett series. The character of the rock with its associated 

 amygdaloids places it unquestionably in the Carboniferous. 



Igneous Rocks 



PRE-GAMBRIAN 



Gahbro. — West of Iron Mine Hill is a mass of highly altered gabbro. 

 It is surrounded by pre-Cambrian schist and Milford granite. Several 

 inclusions of the gabbro have been found in the cumberlandite of Iron 

 Mine Hill. A mile west of the West Wrentham railroad station, near 

 the contact of the Milford granite and the quartz diorite, is some pre- 



20 Emerson and Perry : Op. cit, p. 38. 



