What is pertaining to, or resembling, an abyss; bottomless; unending; profound. Geology gives one the same abysmal extent of time that astronomy does of space. Carlyle called?

abysmal — Pertaining to, or resembling, an abyss; bottomless; unending; profound. Geology gives one the same abysmal extent of time that astronomy does of space. Carlyle. (Webster's 1913.)

Sources