sea-wall towered above us. We passed through the water-gate with its
gigantic hewn prisms of basalt and landed beside a half-submerged
pier. In front of us stretched a series of giant steps leading into a
vast court strewn with fragments of fallen pillars. In the centre of
the court, beyond the shattered pillars, rose another terrace of
basalt blocks, concealing, I knew, still another enclosure.

"And now, Walter, for the better understanding of what
follows--and--and--" he hesitated. "Should you decide later to return
with me or, if I am taken, to--to--follow us--listen carefully to my
description of this place: Nan-Tauach is literally three rectangles.
The first rectangle is the sea-wall, built up of monoliths--hewn and
squared, twenty feet wide at the top. To get to the gateway in the
sea-wall you pass along the canal marked on the map between Nan-Tauach
and the islet named Tau. The entrance to the canal is bidden by dense
thickets of mangroves; once through these the way is clear. The steps
lead up from the landing of the sea-gate through the entrance to the
courtyard.

"This courtyard is surrounded by another basalt wall, rectangular,
following with mathematical exactness the march of the outer
barricades. The sea-wall is from thirty to forty feet high--originally
it must have been much higher, but there has been subsidence in parts.
The wall of the first enclosure is fifteen feet across the top and its
height varies from twenty to fifty feet--here, too, the gradual
sinking of the land has caused portions of it to fall.

"Within this courtyard is the second enclosure. Its terrace, of the
same basalt as the outer walls, is about twenty feet high. Entrance is
gained to it by many breaches which time has made in its stonework.