A cactolith is a quasi-horizontal chonolith composed of anastomosing ductoliths, whose distal ends curl like a harpolith, thin out like a sphenolith, or bulge discordantly like an akmolith or ethmolith.
Ductoliths are horizontal plugs of teardrop cross section, or a headed dike.
Harpoliths are large, sickle-shaped intrusions injected into previously deformed strata, intruding horizontally in the direction of maximum orogenic displacement.
A sphenolith us a partly concordant, partly crosscutting injected body of igneous rock, in which country rocks are overturned in some sections.
Akmoliths are intrusive bodies injected along a decollement, which send numerous tongues into the overlying folded rocks.
Ethmoliths are cross-cutting bodies of plutonic rock that narrow downward and are thus funnel-shaped.