A hand-lettered label accompanies the painting; apparently these images were exhibited with the labels. It explains how the race came about:
In 1665 Governor Nicholls and the Counsel held court at what is now the town of Hempstead. A turf race-course was established there called Newmarket situated at Salisbury Plains. This eventually became Garden City, L.I. As a result of this meeting the sport of horse-racing began in this country.
Frederick Elmiger was an American illustrator. He frequently produced series on historical themes for Donald Art Company in Port Chester, New York, publishers of posters, lithographs, and artists’ prints. These included scenes from American history, Revolutionary war uniforms and vintage automobiles. At the time of his death he was living in Larchmont, New York.
DeWan, George. “Legacy: America’s First Racecourse.” Newsday. 2007. http://www.newsday.com/community/guide/lihistory/ny-history-hs312b,0,5912509.story (30 April 2007).