There are a list of suggested starter spellbooks on page 38 of the rulebook.
The Priestess has a Geyser attack spell listed at the bottom of her starter spellbook.
However, this spell is supposed to be a Jet Stream.
If a Beastmaster and a Priestess duel each other and decide to use unmodified versions of these default spellbooks as originally printed, there will be a shortage of 1 Geyser unless the Priestess takes the Jet Stream spell instead.