160 BULLETIN OF THE 



and are bordered by a fringe of sericite. The optical examination com- 

 bined with chemical analysis led M. Renard to identify these plates 

 finally as ilmenite. In another rock (Phyllite ottrelitifere de Mon- 

 therme) they occur with ottrelite. These metallic plates had been 

 observed elsewhere by M. Eenard and others, but their true nature not 

 determined. 



Minerals of the ottrelite family ("phyllite," chloritoid, masonite, etc.) 

 have been described from the rocks of New England by various miner- 

 alogists, and by T. Sterry Hunt from tlie palaeozoic schists of Canada. 

 The occurrence of this mineml in Maryland, in phyllite, has recently 

 been mentioned by G. H. Williams.-' 



In the complex of gneisses, schists, and massive crystalline rocks 

 which cover the larger part of New England, there are certain areas of 

 partially altered sediments, the palaeozoic age of which has been estab- 

 lished by fossils or stratigraphic considerations. One of the most im- 

 portant of these is the strip forming the western edge of the Green 

 Mountains, which has been proved by the labors of Dana, Wing, Wal- 

 cott, and others to belong to the Cambrian and succeeding periods of 

 the Palaeozoic. These " Taconic rocks " consist of quartzites, crystal- 

 line limestone, phyllites of various kinds, and fine-grained gneisses, with 

 occasional conglomerates, especially near the base. That a large part 

 of the more highly crystalline rocks to the eastward, in Massachu- 

 setts at least, represent the same series still further metamorphosed, 

 appears to definitely result from the work of the United States 

 Geological Survey done under the direction of Professor Pumpelly, now 

 going to press. 



Another important area of metamorphosed palaeozoic sediments oc- 

 curs in the eastern part of Rhode Island, on the shores of Narragan- 

 sett Bay, extending northward into Southerii Massachusetts ; it is of 

 Carboniferous age. The rocks are conglomerates, coal-beds, shales and 

 schists of various kinds, which like the Cambrian rocks of the Green 

 Mountains are intensely crumpled and metamorphosed. 



There are two well-known localities for ottrelite in or near this 

 region : one that of the ^fasonite from Natic, R. I., described by 

 Jackson^ in garnetiferous mica schist which occurred as glacial boulders, 

 the other that of the ottrelite (Xewportite) from the vicinity of New- 

 port, R. I. ,Mr. T. N. Dale says of this occurrence, " Boulders and 

 pebbles of ottrelite schist abound about Newport, but I have failed to 



1 Jolins Hopkins Univ. Circulars, September, 1889. 

 - Geology of Kliode Island, 1840, p. 47. 



