I have 34 Geologist kittens but the town census only shows the newest 10 kittens not letting me promote any others. What's up with that?
As a work-around you can temporarily "unassign job" the ones you can see, then switch the job selection menu away and back to see some more. With 34, you'll have to unassign at least 24 in total to see them all.
You can, at least, keep clicking promote on each worker until it stops helping.
Then reassign everycat and carry on.