Chemistry and Physics. 425 
2d. That the chemical constitution of the anhydrous mineral is 
closely allied to that of Biotite. 
Culsageeite or the Vermiculite of the Jenks Mine, North Carolina. 
—the vermiculite at this locality occurs in close contact with 
readily hexagonal or triangular plates, produced by the truncation . 
of the 60° angle of the rhombic plate, on a line parallel to the 
Shorter diagonal of the fundamental rhomb. The plates most 
c=] 
: e 
shading represent the position of the plane of 
the optical axes. This represents what we may 
call an ideal macle: for I have seldom been 
oO han 
the North Carolina vermic' 
he a ; 
Unequally developed. On many of wonky see = 
: ie pe: ©: . 
macling is externally marked by the eminent cleavage or jointing 
