Around 4 million years ago during a much warmer climate, Gulf St Vincent lapped against the Mt Lofty Ranges. Marine molluscs including clams, mussels, oysters, cockles, and scallops proliferated in the warm sea and the shells accumulated on the sandy shallow sea bed of the Pliocene Epoch. Over the next 2 million years the deposit of shells and sand in the Adelaide Basin formed extensive deposits of richly fossiliferous calcareous silt and sandstones. It is recognised that the stone from the deposit is not a limestone because calcium carbonate does not form the major component of the matrix. Hence a calcareous sandstone formed instead of limestone.
Quarrying into the banks of the River Torrens on the present sites of the Elder Park, Torrens Parade Ground, Festival Centre and Adelaide Railway Station produced the white-to-cream coloured “Adelaide Limestone”. Principal activity in this government-run quarry industry was in the 1840s and 1850s and surviving examples of this stone include Holy Trinity Church (1838), Government House (1840), Adelaide Gaol (1841), and Old Parliament House (1854). These are some of the oldest surviving buildings from the South Australian colonial period. The holes created by the quarries form the existing landform in the area from Adelaide Railway Station to Torrens Parade Ground.
At the Listed Coordinates a small section of the former building stone quarry is exposed. It is not possible to access the quarry face but the features are clearly visible from the footpath. You will get to see the stone close up in the next two waypoints. White “Adelaide Limestone” (Hallett Cove Sandstone) forms a wall up to 2m high with overlying Pleistocene Burnham Limestone and Hindmarsh Clay. (Note construction has denied access to this site)
At Waypoint Parliament you are standing in front of Old Parliament House. White “Adelaide Limestone” was used in the construction of the eastern section of the building during 1854. The extension to the west was built 1874-76 from Mitcham Sandstone. The addition at the rear (north) of the building was constructed using Dry Creek Bluestone in 1880s.
At Waypoint Church you are standing in front of Holy Trinity Church recognised as the oldest extant building in Adelaide. “Adelaide Limestone” was used in the construction of this building during 1838. The “Adelaide Limestone” can be seen in the lower sections of the front and side walls.
To log the cache send the cache owner an email with the answers the following questions. Please do not post your answers in your log. You are encouraged in your log to comment on what you enjoyed or found interesting at the locations during your visit, in particular the condition of the quarry face.
Q1: A metal object is visible in the middle of the quarry face. Describe the object. (This question is optional until access is allowed to the area)
Q2: Compare the white stone used for the eastern and western wings of the Parliament building. Remember east is “Adelaide limestone” and west is Mitcham sandstone. Look at the stones either side of the copper drain pipe to the right of the green doors. Compare grain size and texture. Take note of the colour.
Q3: Stones near the church front door contain many fossils and casts. Also check the stones in the alcove on the east side of the building. Describe the fossils you see. Size and shape.