Deep inlets cut by the sea into Scottish coast are called what?

Any measurement of the west coast of Scotland must be very indefinite till we ascertain ... This line cuts the large Island of Skie, which is only separated 'from the ... of the coast is indented by deep and generally narrow inlets, called Lochs. 22 and 23. This line of coast is exceedingly irregular; it contains the deep inlet of Loch.

The Answer is firths