Base Ball. - Two games were played last Sunday, one between the East St. Louis Base Ball Club and the "Dirty Stockings," in which the score stood: East St. Louis Club, 41; Dirty Stockings, 11. The other match was between two colored clubs, the St. Louis Mutual, and the Polar Star of East St. Louis, in which the score stood: St. Louis Mutual, 26; Polar Star, 18.
-East St. Louis Gazette, July 6, 1872
Secondly, this is the earliest reference I've found to a black club on the east side and it's certainly possible that the Polar Stars predated the East St. Louis Club and the Dirty Stockings. Also, this is, I believe, the second earliest reference to a St. Louis black club that I'm aware of. We have the 1870 reference to the St. Louis Base Ball Club but almost everything else I have comes from after 1874.
And I found all of that in one article. How about that?