Pyramids with tombs of the Tartarian Kings?

I am not quite sure what I spotted here, but there it is. No clue why the word "Sepulcres" is being used. It means "Tombs" when translated from the Catalan language. Essentially we end up with:

• Mount Alchai where the Tombs are of the Kings of Tartary.

These tombs are (or were) located in the North-East of contemporary Russia.
This map sure does have some interesting things mentioned...


KD: Would be nice to find out if our Russian counterparts are looking for any possible leftovers at that location.