Following the walk I went on last night, this is how The Concise Oxford Dictionary Of English Placenames explains the origins of the Norfolk village name of Lamas.
Lamas, Norfolk. Lamers in Domesday Book, Lammesse in 1044, Lammasse in 1186. Old English lam- or lamb-mersc ‘loam marsh’ or ‘marsh where lambs were kept’. The first alternative seems preferable.
So, because the word origins of loam and lamb can’t be separated out, the dictionary suggests the two alternatives and thinks loam marsh is more likely. It does seem like fertile soil today, so the dictionary is probably right, but I much prefer the idea that this village name has been in existence for a century and is named from when lambs were grazed here.