2 2a-2 2b Biotite from Lyon Mountain. Clinographic projections 

 showing types of twins. Forms: c (ooi), b (oio) and /j. 



(in) 



23a Titanite from Lyon Mountain. Orthographic projection 

 showing forms: c (001), a (no), b (010), m (no), n (in), 

 i] (221), t (in), and I (112) 



23b Clinographic projection of same 



23c Clinographic projection on a plane at right angles to that 

 shown in 23b and showing a crystal of the same, habit 

 twinned parallel to a 



24a Apatite from Lyon Mountain. Orthographic projection show- 

 ing type of crystal of secondary derivation. Forms: c 

 (0001), m (1010), a (1120), r (1012), x (ion), y (2021), 

 ^ (7073). 2 (3031), 5 (1121) and^x (2131) 



24b Clinographic projection of same 



