Cliff faces along coastal Hampden look like many others around New Zealand's 18,000km-long coastline, but hidden beneath the surface are minute fossils smaller than a pin head which hold vital information about the world's climate between 40 million and 50 million years ago.
They come from the Eocene period, when there was major change in the global climate, spanning the transition from a greenhouse world to the development of major Antarctic ice.
Those fossilised micro-organisms from the Hampden cliffs are being used by scientists around the world in climate studies, particularly on how temperatures changed between greenhouse and icehouse climates.
That will give greater understanding of current and future climate change.
One scientific paper was publicised recently.
Dr Catherine Burgess, of Cardiff University's School of Earth and Ocean Scientists, led a team which used the fossils to show that 40 million years ago there were warmer seas, with little or no ice in the Antarctic, and Hampden would have been about 1100km further south.
Analysing the calcified fossils indicated the sea temperature was 23degC to 25degC at the surface and 11degC to 13degC where the fossils were originally deposited, about 200m to 400m below the ocean's surface.
The fossils also indicated the greenhouse gas carbon dioxide levels 40 million years ago were similar to those forecast for the end of this century and beyond.
Wellington-based Hugh Morgans, of GNS Science, helped gather samples from the Hampden cliffs in February 2005.
He has been taking samples from that area for quite a long time.
"It has some of the earliest examples of paleontology in New Zealand," he said.
They were taken from sections of the coast from Moeraki, past Hampden to Lookout Bluff.
The samples taken for Dr Burgess were about 2.5km north of the Hampden beach.
"We selected material from a number of locations, cutting a channel into the cliff to take out samples every 5cm or 6cm. It was quite a detailed study," Mr Morgans said.
The sites were chosen because the micro-organisms were very well preserved and the results from analysing them would be very accurate, he said.
The quality of the fossils was what made the Hampden area so outstanding and important internationally.
"They are the best preserved that I have personally seen in New Zealand . . .
Some of the fossils under the microscope look like they have been taken out of the water only a couple of hours ago."
That was important because the geochemical composition was accurate and had not been contaminated.
The fossils were of interest not only to New Zealand researchers.
"There are a lot of people and labs around the world very keen to get their hands on these [Hampden fossils]."
That was not only because of the quality, but also the location.
"If you look around and see where New Zealand is, there are not a lot of other locations you can get data from.
"We have an important role to play in the worldwide understanding of climate change because there are few places in this part of the South Pacific.
"Geographically, there is a big hole which New Zealand fills in," he said.
The fossils were between 0.2mm and 0.5mm - "about the size of a full-stop".
Analysis of the fossil's composition could help identify what the climate was like 40 million years ago.
It could tell how warm surface water was.
"What we examine is how fast they develop when they were growing using elements from sea water.
The temperature of the sea water affected those elements," Mr Morgans said.
While Dr Burgess' team had completed one part of the study, other papers would be published as more results became available.
However, there were ongoing studies by GNS Science in conjunction with other work being done in North Canterbury and Marlborough.
Results would show there were paleo-climates in high southern latitudes warmer than now.
"We are trying to find places where, in the past, there has been considerable climate change and quite quickly - over several thousand years," he said.
Taking samples from different layers in the cliff face covered a time-frame of 70,000 years, showing warming and cooling of about 1.5degC every 18,000 years.
A combination of this, more recent times and what was happening now gave a broader overview of what could happen to the world's climate.
"Looking 40 million or 50 million years ago gives us a whole lot more information," he said.
Not only could the fossils provide information, but also the sediment in which they were found, including on how land masses had shifted.
