The Correspondence of Caspar Georg Carl Reinwardt - DWC - KNAW

Van Heiningen / 46
H. On the origin of coral reefs
[Speech, delivered at the occasion of a public meeting of the ‘Eerste Klasse’ of the
‘KNI’, held in 1831]
Reinwardt gives a physico-geographical description of the condition of
the various coastal regions of the Dutch East Indies, in which he makes
use of what already has been written by other authors. With respect to the
continuous growth of the coasts he observes that for that reason several fast
growing plants have been created (by God), which can hold the soil particles,
washed down from the thickly grown mountain slopes by the abundant
rain showers and river water, such as the herbs Convolvulus maritimus and
Dolichos maritimus, the shrubs Guilandia Bonduc and Bonduccella and the
trees Acanthus ilicifolius L. (the ‘djeroedoe’),Acanthus ebracteataVahl, Nipa
fruticans L. (the ‘beach palm’, or ‘atap’) and finally the ‘mangi’ or ‘mangroves’
(Rhizophora and Brugiera).According to the reports, received by him, these
plants are among others growing on the beaches of the islands of Java and
Borneo.
During their long history, the Indian islands must have been subjected to
considerable changes. Reinwardt is convinced that in the course of time several
islands have merged, as a consequence of the supply of large quantities
of alluvial soil particles from the steep slopes, which are ending close to the
beaches. In this way the island of Borneo has originated from several islands.
Thereupon, Reinwardt discusses the origin of the coral reefs. All islands,
except the ones, which have to be regarded as young volcanoes, are surrounded
by a more or less circular coral reef, which protrudes into the sea.
As a consequence of the continuous formation and deposit of the ‘vormende
stoffe’ (‘formative substance’), the maze of coral continues to grow
on. The recently developed coral organisms produce a petrifying hull, after
which the living organism starts to die. This process goes on for ages and
ages. Several islands are more than 200 meters high. Reinwardt knows that
other authors have witnessed this phenomenon on the Bermudas, while
he himself has had the opportunity to observe it on the islands of Madura,
Solor, Timor, Kesser, Groot-Banda and Amboina. The scientists and travellers
Peron and Baudin, who have also studied the formation of coral islands,
have established these facts, or at least they have succeeded in making these
assumptions very plausible. In Reinwardt’s view, it is inevitable to accept the