marginal note vs vellum

marginal note

noun
  • A note in the margin of a document. 

vellum

noun
  • A writing paper of very high quality. 

  • A type of parchment paper made from the skin of a lamb, baby goat, or calf. 

How often have the words marginal note and vellum occurred in a corpus of books? (source: Google Ngram Viewer )