Southern vs southly

Southern

adj
  • from or pertaining to the southern part of any region 

  • from or pertaining to the South, the south-eastern states of the United States, or to the inhabitants or culture of that region. 

name
  • A surname. 

southly

adj
  • Synonym of southerly 

adv
  • Synonym of southerly 

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