Outflows of resinResinosisalro come under this general heading; but although some resin-fluxes are traced to the destructive action of Agaricus melleus in Conifers, others, as well as certain forms of Gummosis, are still in need of explanation.
Besides the plant beds extensive outflows of basic lava rest directly upon the Cambrian and Ordovician strata.
The cyclonic inflows and anticyclonic outflows, so characteristic of the belt of westerly winds the world over, are very irregular in the Cord illeran region; but farther eastward they are typically developed by reason of the great extent of open country.
The existence of outflows or springs of gas in the region west of the Alleghanies had long been known, and much gas was used for illuminating purposes in Fredonia, New York, as early as 1821.
- The oldest rocks in Brecknockshire are the Llandeilo shales and intrusive diabases of pre-Llandovery age which near Builth extend across the Wye from Radnorshire; another patch with volcanic outflows comes up at Llanwrtyd, and at both places they give rise to mineral springs.
In the middle of Iceland, where the geological foundation is tuff and breccias, large areas are buried under ancient outflows of lava, which bear evidences of glacial scratching.
In the Archean region these are very noticeable near Lake Itasy, in the massif of Ankaratra (an ancient volcano) and in Vakinankaratra (at Betafo, Antsirabe, &c.); while there are numerous outflows of doleritic rocks, probably from faults, along the eastern side of the island and almost parallel with the coast line.
Outflows of lava and tufa cover the mountain sides and fill up the valleys.