418 Mr. WHEWELL on the Classification 
SQUARE-PYRAMIDAL SYSTEM. 
Example and Figure. Class. Combination. 
Class III. 
Sq. Pyr'. Garnet 2Q2,eQ2| No. 3. pQm, ©Qm 
Mohs, Vol. II.96.e f 
In Mohs these are (P)* Sq. Pyr', Garnet 2Q2,Q4| No. 4. pQm, gQn 
and (P+ 1). i. 06. 7. te when pm=qn 
Thus Q5,3 Qe 
2Q3, 4Q} 
Class IV. | Plagihedral. 
Class V. | Hemihedral. 
3 
(2 = pP- 3) Sq. Pyr. Copper pyr. 
h’Q, h’2Q, FQ, bi Q3 h pQm 
In Mohs r *3 ee f h’q/ Qn 
e II. 178. 
OBLONG-PYRAMIDAL SYSTEM. 
Remarks. Example and Figure. Class. Combination. 
Class I. pP, qP 
Topaz OP, =P, P, »P | No.1. pP, gP 
so ™m 
Mohs, Vol. II. 34. 
