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Use "pyrogenous" in a sentence
"It is, however, much more common in alluvial grounds than among primitive and pyrogenous rocks."
"I place pyroxenic amygdaloid and phonolite (porphyrschiefer) at the end of the formations of Venezuela, not as being the only rocks which I consider as pyrogenous, but as those of which the volcanic origin is probably posterior to the tertiary strata."
"I consider as pyrogenous, but as those of which the volcanic origin is probably posterior to the tertiary strata."