STEN COTE GINA AUN DD VER TAELA INA 139 
Ausscheidung) is reserved for the masses (whether isolated or in 
streaks) formed by the earlier crystallized or solidified portions 
of the molten magma. The above distinction between ‘‘inclu- 
sion” and ‘enclosure’? was proposed by me ina paper on the 
basalts of Kula in 1894;* and it will be seen that ‘‘enclosure”’ 
corresponds to the generally used term ‘exogenous enclosure,” 
while “‘segregation”’ answers to the longer ‘endogenous enclo- 
b) 
sure.’ The term “segregation” is preferable to “aggregation,” 
or ‘secretion’ since the last three are all in gen- 
eral use with well marked connoted meanings. 
In almost all the eruptive rocks of the region, with the excep- 
tions of the biotite-dacite of Kolantziki, and the hypersthene- 
andesites of Oros and Chelona, there are seen spots and patches 
which differ in color and structure very decidedly from that of 
the surrounding rock. In the great majority of cases these are 
irregularly rounded, some, as at Kakoperato and at the hillock in 
the plain east of Mt. Chelona, roughly spherical or spheroidal, and 
only in a very few cases subangular. The line of demarkation 
between them and the surrounding rocks is very sharp, and they 
vary in size from that of a pea to that of one’s head. Since, as 
will be seen later, these have much the same mineralogical com- 
position as that of the enclosing rock (though differing in struc- 
tural and chemical characters) they must be regarded as true 
segregations—the products of an early differentiation and partial 
solidification of the magma at a presumably great depth, which 
have been brought to the surface as unmelted remains of still 
b) 
‘‘concretion,’ 
larger masses by the erupted lava stream. Such segregations are 
not uncommon elsewhere, but the nearest parallel to these here 
described are those found by Kuch? in the Colombian andesites 
and dacites, as well as those in Ecuadorian lavas described by 
Belowsky,3 both of whose papers are occasionally referred to. 
These segregations are, megascopically, chiefly characterized 
by a fine, but even, granular structure made up of hornblende and 
tAm. Jour. Sci. XLVII, 1894, p. 115. 
2 KUCH, op. cit. pp, 82-84. 
3 BELOWSKY, op. cit. pp. 57-60. 
