lambskin vs sheepling

lambskin

noun
  • The skin of a very young sheep, especially prepared with the fleece still attached. A very fine form of leather. 

  • A kind of woollen cloth resembling this. 

sheepling

noun
  • A little or young sheep; lamb. 

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