While these may look like tanks, they are technically designated as “Combat Cars.” The National Defense Act of 1920 put tanks under the control of the infantry. To get around this the cavalry adopted the term combat cars to get around this. I’m not entirely sure when it was lifted but I assume it would have been later in 1940 when the Armored Force and the forming of the 1st Armored Division.
This picture of the represents a not insignificant percentage of the total armored forces available to the US in 1940 when this was taken. The cavalry formed the 7th Cavalry Brigade (Mechanized). The emblem on the turrets mean this is part of the 13th Cavalry. That’s enough terribly written rambling for tonight.