Two units of the Late Permian Gerringong volcanic facies are exposed on Bombo Headland. The Kiama Sandstone member forms a narrow wave-cut platform and adjacent vertical cliff face around the south-eastern extremity of the quarry. To the north the sandstone dips below sea level and is overlain by about 20m of porphyritic basalt, termed Bombo Latite member. The contact between the two units is well-exposed in the cliff section at the eastern end of the section of the two points comprising the headland. The red-brown colour (due to oxidisation of haematite) of the sandstone contrasts markedly with the grey-black latite, which displays spectacular columnar jointing elsewhere in the quarry. Isolated columns 5-5 meters in height stand adjacent to the coast between the north and south parts of the quarry; just to the north the sea wall exposes cross sections of the columns 1-2.5 metres in diameter, resulting in a 'Giants Causeway' appearance.
Petrographic descriptions of the latite emphasise its conspicuous porphyritic texture; large labradorite to andesine phenocrysts with minor clinopyroxene are set in a groundmass of feldspar microlites with interstital chlorite and iron oxide. The latite is commonly vesicular. Agglomerates or volcanic beccias are developed in some areas of the quarry, e.g. the south-western portion near the access road. This lithology is readily distinguished from the latite by its chaotic appearance and light-coloured matrix.
A capping of cream-coloured weathered latite, still retaining the characteristic porphyritic texture, may be studied at the top of the northern and western quarry faces. This sharpley-defined zone of surface weathering and soil formation overlies relatively fresh rock exhibiting columnar jointing.
The Bombo Latite Member was subsequently intruded by at least five basaltic (monchiquite) dykes of probable tertiary age which flowed around and between the columns of latite often taking 90 degree changes in direction. Early workers (Jaquet 1905 & Harper 1915) mapped and described these dykes but subsequent development of the quarry provided further exposures and obliterated others. Today dykes are mainly in the northern half of the quarry but at least one extends across the floor of the excavation in the vicinity of the isolated columnar stacks. They are of interest due to their inclusions of xenoliths and xenocrysts, which are believed to represent fragments of the earth's mantle incorporated in magmas originating from within that zone. Sussmilch (1905) described xenoliths of hypersthene gabbro, augite peridotite, enstatite peridotite and pyroxenite occurring as rounded fragments and boulders embedded in the monchiquite. From a deeper level of what was probably the same dyke, Wilshire & Binns (1961) recorded hornblendite and glimmerite as the dominant xenoliths. Present exposures of most of the other dykes appear to lack macroscopically visible xenoliths (Percival).
The first recorded reference to the district was by George Bass who anchored his 28ft whaleboat in the sheltered bay (now known as Kiama Harbour) in December 1797.
In the years following 1797 Black Beach provided the main landing place for the first cedar-cutters and settlers. Sailing boats would anchor in the relatively well-protected cove while colonists and supplies would be rowed ashore by open boats. In the ensuing decades Kiama's thriving timber and dairy industries put great strain on the limited cargo and mooring facilities in the cove (Dillon, 1991).
The growth and development of Kiama began with cedar-cutting and was linked to the growth and development of the Colony as a whole. Sea transport became of major importance to the district as vessels under sail and later steam, crowded into the Robertson Basin to load timber, later wheat and dairy produce and eventually basalt for shipment to the Sydney markets (HCNSW, 1986, 8).
The site of Kiama Township was reserved by the Government in 1826 and proclaimed in 1836. The township was first surveyed by Robert Hoddle in 1830 and again by Jacques in 1831, and its streets largely laid out around the c.1825 grant to the first settler and cedar getter, David Smith. Initially the town grew up around the road from the harbour to Jamberoo which travelled up the present-day Manning Street and Bong Bong Street but later a lower track through Pikes Hill (now Terralong Street) was cut. The cutting later became the site of a basalt quarry for which Kiama later became better-known (Graham, 2016, 6).
Cedar getters were the first (settlers) to the area, among those was David Smith, who became the first permanent white settler when he built a residence in Kiama in 1832.
The sheltered cove at Kiama became the principal shipping port for the cut cedar. From the 1820s, six or more coastal trading ships would anchor at any one time awaiting their precious cargoes. The early port was described as a 'tolerable good boat harbour from which nine-tenths of the cedar brought to Sydney is shipped' (Dillon, 1991).
Following the cedar cutting came dairying, which quickly flourished into the staple industry of the region. So successful was this rural activity that a new breed of dairy cow, the Illawarra shorthorn, was developed on these productive pastures (ibid, 1991),
By 1848 the town had two inns, a post office, 2 stores, a church and 18 permanent houses. In 1849 a train linking hte quarry and harbour was built down along Terralong Street and a new jetty relocated to here (ibid, 2016, 6).
Kiama was proclaimed a Municipality in 1859.
Local petitions requesting a general upgrading of harbour facilities were presented to the Colonial Government as early as 1864. Thirteen years later the constructed basin and dockside were completed and named Robertson Basin in honour of the then Colonial Secretary. The upgrading of the harbour was timely as in subsequent years, with the export of newly-quarried basalt, there was a massive increase in coastal shipping. Horse-drawn drays were initially used to transport the stone from the quarry to the loading hoppers at the wharfside (ibid, 1991).
In the 1870s the dairying industry was supplemented by basalt (blue metal) quarrying, now one of the district's major income earners alongside tourism. The state's ever-expanding tram, road and rail network needed vast amounts of basalt, both crushed and in natural cube form (ibid, 1991).
Shortly after 1880 a new road running out of Bombo up over the hill was created to link the town centre and Terralong Street to the relocated jetty, main quarry site and the soon-to-be-opened railway station at Bombo. This road was to become known as Collins Street and became one of the town's main roads and its northern approach. The train came to Bombo in 1887 and in 1888 an extension to Kiama was started (ibid, 2016, 6).
Kiama became a tourist attraction very early in the course of its development and throughout the Victorian era served as a premier seaside holiday resort. The town's popularity was considerably enhanced when, with the opening of the railway, it became more readily accessible from Sydney (HCNSW, 1986, 8).
The train came to Bombo (beach) in 1887, when the line from Sydney terminated here, then known as Porter's Garden Beach (Dillon, 1991).
In 1888 an extension of the railway line to Kiama was started (ibid, 2016, 6). Kiama Railway station opened in 1893 as part of the first completed stage of the Kiama to Jervis Bay Railway which terminated at Bomaderry (Nowra).
By 1914 the horse-drawn drays (transporting stone to the wharfside) system had been replaced by a steam locomotive tramway running along Terralong Street (Dillon, 1991).
Bombo Headland Quarry:
Bombo Headland, an attractive coastal feature in its own right, also retains an added characteristic that increases the area's scenic qualities. Set deep within its contours is the Bombo Quarry. A legacy of Kiama's century-old blue metal or basalt quarrying, this 'moonscape' contains geological features of international importance (Dillon, 1991).
In the early 1880s over 80 men toiled to break up the natural blocks of stone. These were then carted by horse to the harbour at Kiama and the nearby Bombo jetty. The rockfill remains of this latter structure can be seen lying in the northern cove of Bombo headland. The area around the cove is known as the Boneyard. The majority of the quarry workers were housed in a nearby 'tent city'. At the time it was reported that 'the place now the favourite resort of Sunday afternoon pleasure excursionists is beginning to assume a very business-like aspect' and 'the verdant beauty of the fields and slopes of Bombo promises soon to be covered with dust and its quiet caverns and shady nooks to ring with the sound of the hammer and explosions of dynamite' (ibid, 1991).
In 1979 a nomination was received from the Geological Society of Australia (NSW Division) for the Bombo Quarry. The importance of the geological features was brought to the Heritage Council's attention by Dr Suzanne Wass of Macquarie University's School of Earth Sciences. The quarry was owned by the Metropolitan Water, Sewerage and Drainage Board and it was proposed that a pollution control plant be constructed on the floor of the disused quarry.
Following site inspections and lengthy consultations between the Metropolitan Water, Sewerage and Drainage Board, NSW Heritage Council, NSW Planning Commission and other key agencies a Permanent Conservation Order was placed over the site in 1983. It was transferred onto the State Heritage Register in 1999.