"A cactolith is a quasihorizontal chonolith composed of anastomosing ductoliths whose distal ends curl like a harpolith, thin like a sphenolith, or bulge discordantly like an akmolith or ethmolith."
In the 1950s US Geological Survey publications were intensively reviewed for style and accuracy, so it’s a minor miracle that the definition got published. This was Hunt’s way of poking fun at the proliferation of –lith words for various rock bodies (the suffix derives from Greek lithos, stone). The definition has a cult following among geologists – I love to roll it off my tongue at parties, where people then stare at me with more than the usual concerned look – so much so that when it was removed from the Glossary of Geology, the hue and cry was such that it returned to future editions, where it remains to this day.
What Things Are Made Of is to try to open those secret doors to give non-scientists a look at geoscience. Whether I succeed or not can be argued, but I am trying. Will I be the next Simon Winchester (The Map that Changed the World, Krakatoa) or John McPhee (Annals of the Former World)? I’d be the last to compare myself to them, but they give me a clear target for lucid writing to which I aspire.