Susaan Hoi, or Fossil Shell Beach (literally Seashell Graveyard), is
located at Ban Laem Pho in Krabi, in the vicinity of Hat Noppharat
Thara - Mu Ko Phi Phi National Park. Susaan Hoi is a matter of
curiosity and although visitors to Susaan Hoi are told that there
exists only two other similar sites in the world, one in US and
another in Japan, most are either engrossed to this or totally
The age of the fossils at Susaan Hoi is placed as about 40 million
years ago. At that time, Susaan Hoi was a large freshwater swamp.
Eventually, it became landmass. Over time, successive layers of
shell created rock slabs known as "shelly limestone" of over 40cm.
These rest on 10 centimetres of lignite, below which was subsoil.
Due to geographic upheaval, this shelly limestone at Susaan Hoi is
now distributed in great broken sheets on the seashore at Laem Pho.
They look like broken chunks of cement flooring from afar.
There are three sites at Laem Pho to view the shells.
Susaan Hoi Site 1
Site 1 is located west of the Visitor Centre. It crops out as a
rocky beach and can be clearly seen during maximum low tide. The
pan-shaped outcrop is the result of the sinking of the underlying
claystone beds. The fossil bed consists of stubby-shaped gastropods
(Viviparidae family) ranging in size from 1-2 cm.
Susaan Hoi Site2
Site 2 is located at the Visitor Centre. It is exposed as a 1-2 m
thick limestone bed. This limestone bed contains millions of
compacted gastropods and is underlain by 20-40 m thick lignite and
claystone beds. These beds are easily eroded by wave resulting in
the collapse of the gastropod beds.
Susaan Hoi Site
This site can be accessed along the track during low tide. Mollusc
beds at this site are approximately 3 m thick, consisting of long
gastropods and bivalves. The gastropod fossils from this site range
in size from the stubby 1-2 cm to the elongated 4-5 cm forms.
Strata of these three sites of Susaan Hoi are interpreted as having
been deposited in fresh-water lakes during 35 million years ago.
Deposited events are summarized as:
Sediments were accumulated into the basins as clay mixed with plant
remains and gastropod fragments. This indicates the presence of
plants and animals in the lakes.
Plant remains were then accumulated upon clay layers and became peat
In the final stage, clayey sediments were mixed with calcareous
components and abundant shell fragements. This is due to huge
population of gastropods living in fresh-water lakes. Changes in
paleoenvironments and fluctuations of water level resulted in
increasing and decreasing numbers of gastropod population as
recorded in the fossil beds.
The presence of laterite, laterite soil, river and beach sands
overlying mollusc beds indicates that fresh-water lakes became a
landmass prior to 200,000 years.