Czechoslovakia SC 154 With Overprint

I am examining a small collection of Czech stamps and found a SC 154 that appears to be overprinted "Masaryk stol(l?) stadi(?)" and cannot find any reference to same in Google.

It could be a cancellation but appears to be too perfect in appearance and layout. The three lines of text are vertical.

I would appreciate any info that members may have on this.

Thanks,
Donald

Can you supply a scan?

A scan would be helpful.

Are you certain re the second word?

No; the second word could be an "a" for the second letter and there is an accent mark above it - more like a short vertical line than a dot. The last two or three letters of the second and third words are blurred and difficult to see.

"Masaryk" is easy as he was the first President of Czechoslovakia. Perhaps this stamp is an official or a revenue or the text is really a cancellation and is a slogan in favor of the President.

Scan not available.

Donald