BGS house style is to limit the use of hyphens to a minimum.
Hyphens help the reader to link associated words, and should be used where their omission would cause confusion.
Hyphens do not imply range or gradation; this is the role of the en-rule (–).
An adverb ending in -ly followed by an adjective or participle does not need to be linked to it by a hyphen, for example ‘finely laminated’.
Other adverbs followed by an adjective or participle should usually be hyphenated before a noun, for example. ‘a well-bedded sandstone’, ‘an ill-defined horizon’, but a hyphen is not needed after the noun, for example, ‘the sandstone is well bedded.
Avoid a string of hyphens by rephrasing. For example, change ‘on a one-inch-to-one-mile scale’ to ‘on a scale of one inch to one mile’.
Colour terms in which the first element modifies the second are left open, for example ‘the pale grey clay’, ‘reddish orange sandstone’. However, if the elements of a colour term are of equal importance, hyphens are required, for example ‘olive-grey clay’.
A hyphen is not required between the digit and the unit of measurement, but insert a nonbreaking space to keep the two together. However, where the unit of measurement is spelt out, a hyphen should be used, as in the phrase ‘a six-inch sheet’.
Numbers from twenty-one to ninety-nine that are not single words should be hyphenated.
In general do not hyphenate words formed with prefixes. Write ‘subangular’, ‘intergranular’, ‘microfauna’. The chief exceptions to this rule are:
- compounds in which the second element is a capitalised word or a numeral, as ‘post-Dinantian’, ‘pre-1914’ (but ‘Precambrian’)
- compounds that must be distinguished from homonyms, as ‘re-cover’, ‘un-ionised’
- some compounds in which the last letter of the prefix is the same as the first letter of the word following, as ‘co-opt’
- always use a hyphen to avoid words that would otherwise be misleading