261 Warren — llmenite Rocks near St. Urbain, Quebec; 



anorthosite located near Quebec, just north of the Chateau 

 Richer, and known by that name. It is probably distinct from 

 the great mass of anorthosite lying to the north and northeast 

 about the upper waters of the Saguenay. 



The anorthosite calls for no special description. It may be 

 noted, however, that it is rather poor in femic constituents, 

 and that such as occur are largely or wholly altered to chloritic 

 or serpentinous products. The disseminated grains of ilmenite 

 are always highly xenomorphic. Locally the rock shows some 

 crushing, and throughout, the feldspars, which are chiefly ande- 

 sine, show some evidence of strains. 



The Ilmenite 31 cesses in General. — The contacts with the 

 ilmenite bodies are, as a rule, quite sharp, although there is in 

 places some gradation. Along the contacts there is commonly 

 a narrow band of a dark brown mica developed. Small spheri- 

 cal or irregular masses of ilmenite occur at many places in the 

 vicinity of St. Urbain, also narrow dike-like streaks. The 

 larger bodies appear in general to have the form of elongated 

 masses, sometimes dike-like in their general outlines. The 

 elongation follows an indistinct gneissoid structure in the 

 anorthosite, which here has an east-westerly direction. The 

 dip is usually highly inclined, although some of the ore bodies 

 bend over and lie almost horizontally, conforming, doubtless, 

 to local flextures in the enclosing rock. 



Large Deposit of Rutile-free Ilmenite. — One of the two 

 most important exposures of the ilmenite rock is found about 

 one-half way up the hillside, which rises rather steeply directly 

 west of the village of St. Urbain and forms the western rim of 

 the broad valley of the River Gouffre. The ilmenite has been 

 partially uncovered, and probably a few thousand tons were 

 mined many years ago for iron. In fact, the ruins of an old 

 smelter may still be seen just below the deposit. The total 

 exposure at the old workings is perhaps 100 feet wide by 200 

 feet long (east and west.) Good outcrops occur at intervals 

 for some distance to the west along the bed of a small stream 

 which runs down the hillside at this point. On the south side 

 of workings a dike-like body of very massive ilmenite is 

 exposed and may be followed up the hill for some 200 feet. 

 This has an average width of about 10 feet and near its upper 

 end bifurcates, one branch bending off to the northwest. A few 

 feet north of this, another dike, possibly ramifying below with 

 the first, bends off to the north with a flattening dip until it 

 becomes almost horizontal. Just north of this again comes 

 another mass, which has been uncovered over an area measur- 

 ing some 70 feet on a side, with a depth, as exposed, of some 

 20 feet. This is cut near its northernmost exposure by a nar- 

 row streak of anorthosite rock with a nearly vertical dip and 

 an east-west trend. 



