was somewhat impeded. It was not
strange that the crews were frightened at such a sight. It seemed
uncanny and weird, and revived ancient fancies about mysterious
impassable seas and overbold mariners whose ships had been stuck fast in
them. The more practical spirits were afraid of running aground upon
submerged shoals, but all were somewhat reassured on this point when it
was found that their longest plummet-lines failed to find bottom.

[Footnote 515: The situation of this Sargasso region in
mid-ocean seems to be determined by its character as a quiet
neutral ground between the great ocean-currents that flow past
it on every side. Sargasso plants are found elsewhere upon the
surface of the waves, but nowhere else do they congregate as
here. There are reasons for supposing that in ancient times
this region extended nearer to the African coast. Skylax
(_Periplus_, cap. 109) says that beyond Kerne, at the mouth of
Rio d' Ouro the sea cannot be navigated on account of the mud
and seaweed. Sataspes, on his return to Persia, B. C. 470, told
King Xerxes that his voyage failed because his ship stopped or
was stuck fast. (Herodotus, iv. 43.) Festus Avienus mentions
vast quantities of seaweed in the ocean west of the Pillars of
Hercules:--

Exsuperat autem gurgitem fucus frequens
Atque impeditur aestus ex uligine....
Sic nulla late flabra propellunt ratem,
Sic segnis humor aequoris pigri stupet.
Adjicit et illud, plurimum inter gurgites
Exstare fucum, et saepe virgulti vice
Retinere puppim, etc.
Avienus, _Ora Maritima_, 108, 117.

See also Aristotle, _Meteorol._, ii. 1, 14; Pseudo-Aristotle,
_De Mirab. Auscult._, p. 106; Theophrastus, _Historia
plantarum_, iv. 7 Jornandes, _De rebus Geticis_, apud Muratori,
tom. i.p. 191; according to Strabo (iii. 2, Sec. 7) tunny fish
were caught in abundance in the ocean west of Spain, and were
highly valued for the table on account of their fatness which
was due to submarine vegetables on which they fed. Possibly the
reports of these Sargasso meadows may have had some share in
suggesting to Plato his notion of a huge submerged island
Atlantis (_Timaeus_, 25; _Kr