352 Canadian Record of Science. 



plentiful than the biotite, being present in rather large 

 amount. It has the same curiously irregular outlines as 

 the epidote, being sometimes in very slender forms and 

 delicate skeleton crystals and at other times in tolerably 

 stout individuals. The little indentations which frequently 

 form a very delicate and complicated lace work about the 

 edge of the crystals are occupied by whatever mineral the 

 mica happens to be embedded in, sometimes quartz, but at 

 other times orthoclase or plagioclase, and in the great 

 majority of cases when the little arms are so cut that they 

 can be accurately studied, the mineral occupying tbem is seen 

 to have the same extinction and to be continuous with that 

 surrounding the mica, forming in fact, as in the case of the 

 epidote, part of one and the same individual. Sometimes a 

 number of little muscovite crystals situated near each other 

 will be found to have the same orientation, although in the 

 plane of the section there is no connection between them, 

 in fact in one grain of feldspar, probably plagioclase, two 

 well defined sets of small slender muscovite individuals 

 were seen crossing one another at an angle of 55°, the mem- 

 bers of each set extinguishing simultaneously, while -a third 

 set formed of fewer individuals also similarly oriented was 

 arranged in a third direction cutting across these. In Fig. 

 1, (Xos. iv, v, vi), three occurrences of this muscovite are 

 represented, the separated parts in each case having a 

 common orientation. 



The muscovite showing this peculiar structure is fre- 

 quently found immediately in contact with biotite which 

 shows no signs of it, nor is the muscovite a bleached biotite, 

 for no transition stages are ever observed, though both are 

 seen in contact along a sharp line in several cases. The 

 biotite, however, is as above mentioned, sometimes altered 

 to chlorite. The calcite occurs in large individuals, some- 

 times alone and sometimes associated in groups of two or 

 three. They are generally irregular in shape and show 

 the usual twinning. Like the muscovite and epidote it is 

 frequently developed as skeleton crystals, and has been 

 found enclosed in muscovite, in plagioclase, and in un- 



