DOI Seite / Zitierlink:
https://doi.org/10.11588/diglit.2532#0116
BURIAL OF ANCIENT REMAINS
95
times lighter than water, and its carrying- power consequently far less, yet, owing to its
greater velocity of motion, its power of transporting material of certain kinds is fully as
great. On an average the largest sand grain which can he sustained hy ordinary winds is
only 0.1 mm. in diameter,1 so that the material transported hy wind is naturally only the
finest in grain. It must also naturally he dry. Furthermore, since the raising of dust
into the upper layers of the air, where velocities are greater, is greatly facilitated by gusts,
swirls, and eddies, its transportation will he facilitated hy conditions tending to produce
these. Hence, as Udden says, " the conditions favoring wind erosion are a dry climate
and a topography of abrupt and broken reliefs."
It Avill be seen that the climatal and topographical conditions of Greece and especially
of the Heraeum site are highly favorable to wind transportation. There is the dry,
dusty plain surrounded by mountains, the former supplying the material and the latter
aiding by rendering the normal winds gusty and irregular. It was by no means uncom-
mon to see from the excavations the clouds of sand and dust drifting across the plain
below, and the amount of dust raised by the winds from the excavations themselves was
at times a serious annoyance.
As to the deposition of the dust so raised, it is evident that, since its transportation
depends largely on the velocity of the winds, anything tending to check the motion will
tend to deposit its earthy burden. Objects projecting above the surface will do this, so
that any ruins will become a nucleus for aeolian deposits (as they are called) on a small
scale. The growth of grass and bushes will also have the same effect, and the growth
about ruins is facilitated by the presence of the fine aeolian deposits, which, through the
selective action of the wind and other causes, are richer in plant food than the soil they
are derived from, and where also such material is in a more easily assimilable condition.
The application of these remarks to the Heraeum will be deferred to a later page, but
attention may be called to the calculation of Lanciani 2 that dust (largely wind blown)
accumulates on the floor of the Forum of Trajan at the rate of an inch a year, or over
eight feet in a century.
In this connection may be mentioned, for the sake of completeness, the burial of build-
ings and towns in Holland and elsewhere by sand dunes. In this case, however, the
motion of the dunes is a rolling one, the wind blowing the back and top layers of sand
continuously forward, so that the dune moves bodily forward as a whole through the
motion of its component particles.
Water- — The action of water in burying ancient remains is of the highest impor-
tance, and takes place in several ways.
Rain falling on sloping surfaces of earth tends to wash the loose surface matter down-
ward, and hence to bury objects which lie at the bottom of the slope. Rivers and brooks
carry enormous amounts of sediment down from higher to lower levels, where part of the
material is deposited, the rest passing out to sea or being deposited on the bottoms of lakes.
Low-lying sites in river valleys and on plains at the foot of mountains are especially
apt to be buried by such means.
This action of rivers is greatly aided by the occurrence of freshets, where the stream,
much increased in volume and velocity, and hence carrying far greater loads of sedi-
ment than usual, spreads far from its banks and deposits material over areas which
the normal flow never reaches. A well-known instance of this is the site of Olympia,
Avhich was covered largely by material brought down by the Cladeus and deposited in
1 J. A. Udden, Journal of Geology, II. (1894), p. 322. 2 Lanciani, Ruins of Ancient Rome (1897), p. 99.
1
95
times lighter than water, and its carrying- power consequently far less, yet, owing to its
greater velocity of motion, its power of transporting material of certain kinds is fully as
great. On an average the largest sand grain which can he sustained hy ordinary winds is
only 0.1 mm. in diameter,1 so that the material transported hy wind is naturally only the
finest in grain. It must also naturally he dry. Furthermore, since the raising of dust
into the upper layers of the air, where velocities are greater, is greatly facilitated by gusts,
swirls, and eddies, its transportation will he facilitated hy conditions tending to produce
these. Hence, as Udden says, " the conditions favoring wind erosion are a dry climate
and a topography of abrupt and broken reliefs."
It Avill be seen that the climatal and topographical conditions of Greece and especially
of the Heraeum site are highly favorable to wind transportation. There is the dry,
dusty plain surrounded by mountains, the former supplying the material and the latter
aiding by rendering the normal winds gusty and irregular. It was by no means uncom-
mon to see from the excavations the clouds of sand and dust drifting across the plain
below, and the amount of dust raised by the winds from the excavations themselves was
at times a serious annoyance.
As to the deposition of the dust so raised, it is evident that, since its transportation
depends largely on the velocity of the winds, anything tending to check the motion will
tend to deposit its earthy burden. Objects projecting above the surface will do this, so
that any ruins will become a nucleus for aeolian deposits (as they are called) on a small
scale. The growth of grass and bushes will also have the same effect, and the growth
about ruins is facilitated by the presence of the fine aeolian deposits, which, through the
selective action of the wind and other causes, are richer in plant food than the soil they
are derived from, and where also such material is in a more easily assimilable condition.
The application of these remarks to the Heraeum will be deferred to a later page, but
attention may be called to the calculation of Lanciani 2 that dust (largely wind blown)
accumulates on the floor of the Forum of Trajan at the rate of an inch a year, or over
eight feet in a century.
In this connection may be mentioned, for the sake of completeness, the burial of build-
ings and towns in Holland and elsewhere by sand dunes. In this case, however, the
motion of the dunes is a rolling one, the wind blowing the back and top layers of sand
continuously forward, so that the dune moves bodily forward as a whole through the
motion of its component particles.
Water- — The action of water in burying ancient remains is of the highest impor-
tance, and takes place in several ways.
Rain falling on sloping surfaces of earth tends to wash the loose surface matter down-
ward, and hence to bury objects which lie at the bottom of the slope. Rivers and brooks
carry enormous amounts of sediment down from higher to lower levels, where part of the
material is deposited, the rest passing out to sea or being deposited on the bottoms of lakes.
Low-lying sites in river valleys and on plains at the foot of mountains are especially
apt to be buried by such means.
This action of rivers is greatly aided by the occurrence of freshets, where the stream,
much increased in volume and velocity, and hence carrying far greater loads of sedi-
ment than usual, spreads far from its banks and deposits material over areas which
the normal flow never reaches. A well-known instance of this is the site of Olympia,
Avhich was covered largely by material brought down by the Cladeus and deposited in
1 J. A. Udden, Journal of Geology, II. (1894), p. 322. 2 Lanciani, Ruins of Ancient Rome (1897), p. 99.
1