Quotation from: Out of Time's Abyss

Written by: Edgar Rice Burroughs

The entire party was moody and glum. There was none of the
bantering that had marked their intercourse before, even in the
face of blighting hardships and hideous danger. This was a new
menace that threatened them, something that they couldn't
explain; and so, naturally, it aroused within them superstitious
fear which Tippet's attitude only tended to augment. To add
further to their gloom, their way led through a dense forest,
where, on account of the underbrush, it was difficult to make
even a mile an hour. Constant watchfulness was required to avoid
the many snakes of various degrees of repulsiveness and enormity
that infested the wood; and the only ray of hope they had to
cling to was that the forest would, like the majority of
Caspakian forests, prove to be of no considerable extent.