How to Train Your Dragon (in Geology)
According to the tales of antiquity, Tanjong Berlayar was once the mouth of a dragon that guarded the southern harbour of the island of Temasek. This Earthcache aims to unravel the mystery of the Dragon Tooth Gate in Labrador Park, and, perhaps, you’ll also learn a thing or two about the rocks that define the region.
Sailing into the Dragon’s Mouth
The defining landmarks of Keppel Harbour were a pair of large stone outcrops that guarded both sides of the entrance to Keppel Harbour. One of the rocks was located here at the headland of Tanjong Berlayar, and the other was at Tanjong Rimau on Sentosa Island. These rocks were known for a long time, almost as far back as the 14th century. One of the earliest records of settlements on the modern day island of Singapore, by a Chinese traveller and trader known as Wang Dayuan, recorded a place with the name “Long Ya Men”, which means Dragon Tooth Gate. Scholars believe that he was referring to these rocks, which were a prominent landmark for any traveller passing through the region.
Later maps by the Portuguese and the Dutch refer to the rocks variously as Lot’s Wife or Batu Berlayar (from Malay, meaning Sailing Rock), a testament to their prominence on the coastline of Singapore Island. Many traders rounding the Malay Peninsular would use the rocks as a navigational landmark of the Western Entrance to Keppel Harbour, which was one of the many common routes taken. However, the presence of the rocks were forgotten by the 17th Century, when a more southern route was preferred. The rocks were “rediscovered” in the 19th Century, when William Farquhar, then Resident of Singapore, found Keppel Harbour to the west of the Singapore River and suggested that a new harbour be built there.
However, this renewed knowledge of the rocks would signal the death knell for them. As Keppel Harbour gained importance as Singapore’s main port-of-call, replacing the already crowded Singapore River, traffic along the narrow entrance meant that it was more pragmatic to destroy them. So, in 1848, John Thomson, Singapore’s chief surveyor had the rocks blown up to widen the harbour entrance and the harbour lost its faithful guardians.
In July 2005, a replica of the Dragon Tooth Gate was put up near the original spot of the Batu Berlayar. It was meant to commemorate the 500th anniversary of the expedition of the illustrious Admiral Zheng Ho, who embarked on a diplomatic mission across Southeast Asia and South Asia to spread the influence of the Chinese Ming Dynasty and the forge ties with the nations of the region. Today, the replica stands tall, reminded visitors of the grand landmark that once stood here, welcoming visitors to Singapore.
What Made Up the Dragon Teeth?
Some sources claim that the teeth were “craggy granite outcrops”, but this is very unlikely, given the geology of the region. So, what could the Dragon’s Tooth be made out of then?
The south-western part of Singapore is made out of by various beds of sedimentary rocks known collectively as the Jurong Formation. The Jurong Formation extends from the Southern Islands and continues north-west towards the western end of Singapore Island. The terrain formed by this formation are a series of islands and low ridges and hills, which runs parallel to the Bukit Timah Fault. The sediments making up the rock are believed to be a combination of weathered material from Bukit Timah Granite and a mixture of river and marine sediments.
The formation is made up of a number of different types of sedimentary rocks, which includes siltstones, mudstones, sandstones, shales, limestones and conglomerates. More information about how to identify these rocks can be found in an Earthcache on the other side of the harbour, on Sentosa Island.
For today, however, we’ll be focusing on the rocks that could have formed the Dragon’s Tooth. To figure out this mystery, we turn to a prominent outcrop of rocks at the published coordinates. The rocks here are a good example of a sedimentary rock of the Rimau Facies, one of the components of the Jurong Formation.
Sedimentary rocks come in several forms. One of these is sandstone, which is composed primarily of sand-sized particles (0.0625-2mm) in size. Conglomerates rocks are collections of coarse-rocks (>2 mm) of various types glued together by a “matrix”, which acts like a form of natural concrete. They are made up of bits and pieces of other rocks (known as clasts) which are eroded from other sources and stuck together. Now, it’s your turn to figure out what “rocks” make up this larger rock.
Earthcache tasks:
- Inspect the rocks closely. Describe the composition of the rock -- is it homogeneous or made up of different components? If you can see components, what size are they? Based on your observations and the description, what kind of rock do you think this is?
- Compare the colour of the rocks here with the replica of the Dragon Tooth Gate nearby (N01° 15.775' E103° 48.325'). Are they similar? Based on your answer, what type of rock do you think made up the original Dragon Tooth Gate.
- Take a picture of yourself or your GPS at the Dragon Tooth Gate and post it with your log.
You may log the Earthcache once you have sent the email with your answers. There is no need to wait for a reply. If the answers are inaccurate or if there are any issues with the log, we will let you know.