and Volcanic Substances. 221 
rous, porphyritic or amygdaloidal. This is accompanied 
by stones fused, half fused, ignited, heated, or warmed, 
acted on by fire so as to affect their appearance, or not so, 
according to the degree and continuance of the heat, and 
the nature of the stones thus acted on. This statement re- 
quires no proof to persons accustomed to look at volcanic 
regions, or even cabinet specimens of well selected volca- 
nic productio 
All these nr escalch belong to the Basalt of France and 
Germany, and to the whin and toad stone of Great-Britain. 
They belong to no other class of rocks. Every known 
character that Lava possesses, is possessed also in like man- 
ner, — under like sear by the newest fletz trap 
of Werner. Werner himself was aware of it, for — ona 
visit os Paris a few years before his death, he w 
and urged to pay a visit to Auvergne, he steadily décliaed it. 
He had already put the detached masses of Saxon Basalt 
into his Neptunian formations, finding them to repose upon, 
and to alternate with rocks decidedly of Neptunian origin. 
He called them, rocks of the newest fletz trap formation. 
ewest because they were found covering aa alluvial, 
aiid the most recent of his secondary formation 
Fletz, because, covering the fieetz or soidinaiteh rocks, 
they appeared to belong to that series. 
ron oe the hornblende character so observable in 
He to have distinguished between 
Augie and Hornblende as being decisive of the character of 
igneous rocks. 
The rocks usually ranked as flcetz trap, by the Werne- 
rians, are Basalt, Porphyry, Amygdaloid, Greenstone, 
Pitchstone, Obsidian and Pumice. It is hardly necessary 
at the present day, to prove that the three last of these rocks 
are igneous in their origin. I shall take it as conceded that 
they are so. 
eae then to shew, 
the columnar, prismatic, figurate basalt, so com- 
Rao these: ted rocks, is common also among 
the best known active volcanoes, shiek abound in basalt of 
- That Basalt ae decided marks of fire on the sub- 
— ois. wert to it. 
Vou. IV Saas No. 2. | 
