Hmmm.   Why does there seem to be a need to associate Eubie Blake with this Northumbrian tune?

Chevy Chase is a suburb of Washington DC. Blake was born in Baltimore, not that far from DC. Chevy Chase is a rather well known town in the U.S., and moreso if you live in the DC area. In his early days of performing, he traveled the East Coast. He wrote other tunes that he named after towns and locales (Charleston Rag, Baltimore Buzz, etc.)and as Fred mentioned - he could "detect no resemblance at all to the Northumbrian Chevy Chase".   It is highly unlikely (but not impossible) that Blake heard this obscure tune and decided to write his ragtime classic.