In these three examples, you can find different ways of doing it.
It is denoted with "Spoken Title", "Sub-title" or just "Title" instead of the number of the shot/scene.
Here are examples from the links:
(1) The Sidewalks of New York (1923)
Scene 13--The battlers break and glare at
Reagan. One of them, a freckled specimen with
dangerous eyes, asks:
Spoken Title--2
"What's his trade-mark?"
Scene 14--Long shot, as in Scene 12. Reagan
bites a "chew" from a plug of tobacco and then
replies:
(2) The New York Hat
Exterior of house - porch
Room: Girl putting hat on
Sub-title: Sunday morning - She attempts to explain
Room: Man with hat in hand, walking toward door
Exterior of house - fence - gate: Man coming out of gate
(3) The Phantom of the Opera
11. INT. ON BACK STAGE. . AMBER
This is a general shot of the backstage before
the rise of the curtain and must be most interesting
and picturesque. THE GENERAL ATMOSPHERE IS ONE
OF CHAOS and confusion. Sixty stage hands are
moving about the large pieces of scenery. They are
putting up the set for the first scene, the
home of Faust the aged alchemist. In evidence
are carpenters, florists, drapers, curtain hangers,
firemen, call-boys and property men. In the rear
of the stage is the dressing room corridor
leading to the numerous dressing rooms.
TITLE M. DEBIENNE AND M. POLIGNY, MANAGERS
OF THE OPERA HOUSE.
12. INT. MANAGER'S OFFICE.
FULL SHOT
Discovered M. Debienne, M. Poligny and M. Lavelle,
Secretary. The corpulent M. Debienne and the
slender M. Poligny appear to be in the throes of
a great mental stress - Debienne mops his perspiring
forehead and exhales deep sighs of despair while
Poligny stares into space with a gloomy expression --
at his desk nearby sits M. Lavelle, their secretary,
a bright dapper fellow, whose whistling at such
a trying moment grates on the managers' nerves--
every now and then he glances with contempt and
annoyment at the others' discomfiture--Debienne
glances despairingly at a large volume which lies
before them on the table open.