It is apparent that in many cases lichens are quite indifferent to the substrata on which they occur, whence we infer that the preference of several for certain substrata depends upon the temperature of the locality or that of the special habitat.
The substrata are mostly sandstone of various formation, and granitic gneiss, of which the rocks are mainly composed.
The principal substrata are, sandstone, amygdaloid alternated with trap, and red porphyry.
It was found to be normal for the type of has substrata that occurs in the district.
The principal substrata are limestone and freestone of excellent quality; and along the banks of the river, ironstone is found in abundance.