Thank you for your information on Myer Asch. My data on him being in command of the 4th MO Vol comes from a genealogy source. It was written about the town of Erwin, NY and stated Myer Asch was living in the town and serving in the war. Then it stated that he was made Colonel. I will have to track down the author and see where that information came from.
Asch served as Chief of Cavalry for Gen Pope in the Dept of the Northwest (after Pope was relieved after Second Bull Run. Do you happen to know where the records of the Dept of the Northwest are kept and how to retrieve them?