That's very cool you found the cast steel stamp. I think 'cast steel' was advertised on axes in the late 1800s to very early 1900s to indicate a high quality steel (not that the axe was formed through a casting process).
Here is a similar looking axe with a cast steel stamp. You can look and see if you think the style of the stamps looks similar or not
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though there were many manufacturers who advertised cast steel on their axes. I think the older collins axes said cast steel, and I know Beatty cleavers said cast steel, they made some axes like hatchets and fire axes but I've never seen a beatty jersey/kentucky axe.
If you are interested in trying to narrow down the manufacturer, you can do google searches for cast steel axes and look at a bunch of pictures of different axe stamps and see if any match up to your stylistically. I'm sure you have a row of text above that cast steel stamp that indicates the manufacturer, and the poll isn't "TOO" damaged so you might be able to tease it out with the right amount of cleaning and light angles. I wouldn't wire it much more, but you could dunk the poll of the axe in evaporust for a day or so, periodically scrubbing with a toothbrush until the rust is all out of the pits, and that may reveal something. I've had good luck revealing very faint stamps with evaporust.
even if you don't figure it out or care to, you at least know that your axe head is over 100 years old.