The expression of syllable weight in terms of moras leads to two major descriptive problems for phonological metrical theory using iambs and trochees to describe stress.

On the one hand, there are languages with long vowels and geminates, such as iambic Pacific Yupik (Hayes 1995: 302) or trochaic Wolof (Bell 2003), where only the long vowels, but not the syllables closed by a geminate, count as heavy for stress purposes. On the other hand, there are languages, such as Cayuga, in which closed syllables do not make a syllable heavy and is treated as light, that is, as monomoraic, by stress, but where laryngeal metathesis implies that a closed syllable is heavy. In this talk, we will show that a two-layered mora model, neither for Wolof nor for Cayuga, is necessary and we will propose a straightforward simple alternative, within the framework of Harmonic Serialism (McCarthy 2016), that does allow to directly express the relation between stress and metathesis.