230 
IOWA ACADEMY OF SCIENCE 
SiO 62.51 58.07 
AM)3 16.62 15.83 
FeaOa 1.12 2.97 
FeO 3.75 3.89 
MgO 3.30 5.56 
CaO 5.10 6.70 
NasO 4.28 3.89 
K 2 O 1.86 1.73 
H 2 O .68 .41 
TiO 1.02 1.27 
P 2 O 5 23 .29 
Cr20s .01 .01 
MnO .10 .06 
SrO .03 .04 
BaO 14 .07 
LUO ...... Tr. Tr. 
100.75 100.79 
Volcanic phenomena about Citlaltepetl are very extensive and 
very complex. This volcano is only one of the later manifestations 
of the general vulcanism of the district. On the slopes and plains 
below are found many of the very latest and the dying explosive 
effects. One of the small parasitic ash-cones lies near the city of 
Julapa. 
