While I was reading a book, I chanced on a clause that I found very odd. It says,
The sea, inches beneath me yet too far for my eyes, buffeted the raft.
At first I thought the italicised part was a nonessential clause, but I was reasonably confident that there would have to be a word which before the word inches to make it grammatically correct. So my second guess was that it should be a participle clause with “inches… my eyes” being a participle phrase; but then I thought there should be a participle like being before the word inches.
Which is correct?
You’re correct that it’s a nonessential clause, but that’s rather a semantic and broad type—a participle clause can be nonessential as well, just like more or less any other type of clause can.
The fact that this clause comes after the noun that it modifies (sea) means that it is a postmodifying clause.
More specifically speaking, since it does not have a verb (the relative pronoun which and the copular verbal form was have been deleted through whiz-deletion) means that it is a verbless clause.
The fact that there is an underlying which is (which can be restored with no change in meaning) indicates that it is a relative clause, and as you have probably noticed, the intonation and semantics of the sentence imply that it is a non-restrictive relative clause.
In other words, to use the terminology used by Pieter de Haan on page 81 of his book Postmodifying Clauses in the English Noun Phrase: A Corpus-based Study, it is a postmodifying verbless non-restrictive relative clause.