Solfatara

Under these solfataras, (which, at each eruption from the volcano, emitted greater quantities of hot steams) are several hot wells, close to the high-water mark, which, however, seem not to be in the least sulphureous.

Holmes calls these active vents solfataras, so evidently we are at the type locality for this kind of thing.

Vents that produce steam alone are fumaroles, or solfataras if laden with sulphur; impressive, but rarely exciting, they are more common on drier volcanoes than in hydrothermal basins.