AGATES. 
167 
the former being the tliicker of 
the two. 
Uruguay. 
84a. Section of Amygdaloid 
tilled with Chalcedony in concen- j 
trie and horizontal layers, the two 
systems continuous with each 
other. 
85 and 86. Portions of a Ciial- 
CEDoxic Amygdaloid, showing 
horizontal and concentric layers ; j 
the former partly clothed with { 
Amethyst crystals. 
Uruguay. 
86a. Portion of an Amy^gdaloid 
tilled with Chalcedony in hori¬ 
zontal and concentric layers, the 
latter showing an inlet of infil¬ 
tration. 
Montrose. 
87. Segment of Amygdaloid 
showing well the continuity of the 
horizontal and concentric layers. 
V 
Uruguay. 
87a. Portion of an Ajiygdaloid, 
nearly filled with Chalcedony in 
horizontal and concentric deposits, 
the latter exhibiting several tubu¬ 
lar inlets. 
88. Fragment of an Amygda¬ 
loid, clothed externally with 
Delessite, and consisting inter¬ 
nally of stalactitic Cacholong with 
Amethyst. 
Galgenberg. 
89. Fragment of Amygdaloid, 
showing deposition of a first layer 
of Chalcedony,second of Amethyst, 
and third of stalactitic Chalcedony 
with a tendency to form crystals. 
Galgenberg. 
90. Part of an Amygdaloid of 
white Chalcedony, with a tube 
through which the material has i 
been introduced. The cracks i 
which surround it have been pro¬ 
duced by the heating of the sub- | 
stance to obtain a whiter colour. ! 
By some these have been taken ' 
for organic forms and called | 
Chalcedon-thierchen.” ! 
Uruguay. 
91. Chalcedony', with similar 
tubular openings, through which 
oxide of manganese has been intro¬ 
duced, forming Dendrites. 
Uruguay. 
92. Chalcedony with tubular 
opening, without cracks, not hav¬ 
ing been subjected to heat. 
Uruguay. 
92a. Chalcedony Amygda¬ 
loid, with tubular inlet. 
93. Segment of a Compound 
Amy’GDALOID, with irregular ar¬ 
rangement of Chalcedony, Agate- 
Jasper, and Amethyst, partly 
caused by fragments of the outer 
coating of Delessite which have 
fallen in. 
Galgenberg. 
94. Segment of a Chalcedony 
Amygdaloid, with coating of 
Delessite. 
Galgenberg. 
95 and 96. Portions of an 
Amygdaloid, filled with an ir¬ 
regular mass of Delessite frag¬ 
ments, Quartz, and Calc Spar. 
Bergen, near Oberstein. 
97 and 98. Portions of a similar 
Amy'gdaloid, containing more 
Silica in proportion. 
Bergen. 
99. Portion of an Amygdaloid, 
irregularly filled with Delessite 
and Agate-jasper. 
100. F ragment of Amy'Gdaloid, 
consisting of Onyx-like Chalce¬ 
dony, and Amethyst, the latter 
strongly coloured by Delessite. 
Galgenberg, near Idar. 
100a. Section of Ayiygdaloid 
of Chalcedony and Amethystine 
Quartz, with Delessite. 
Montrose. 
101. Irregular mixture of frag¬ 
ments of Delessite, cemented by 
Chalcedony and Amethyst. 
Galgenberg. 
102. Section of Chalcedony with 
Delessite. 
