Sign 1 Crosslands Interpretive Trail
From the north-eastern end of the Crosslands’ car park follow the bitumen service track, noting Swamp Oaks Casuarina glauca, the mangroves by the creek, and the
remnant trees from the former open-forest (Bloodwoods and Turpentines).
Sign 2 Swamped out the back
To the right of the picnic shelters follow the Great North Walk (Calna Creek 1.3 km) using the boardwalk across the swamp. This boardwalk is suitable for wheelchair
use.. This swamp was originally a channel made by Burton Crossland to assist his boat building and construction activities. It has now formed naturally into a backswamp. On quiet days a lyrebird may be heard calling near here.
The small plant with bright green angular leaves growing abundantly is New Zealand Spinach Tetragonia tetragonioides, an edible bush food.
At the end of the boardwalk you come to the start of a mangrove section featuring two species: the River Mangrove Aegiceras corniculatum and the Grey Mangrove Avicennia marina var. australisca. Patches of Sea Rush Juncus kraussii can
be seen growing in the shallow water.
The track continues behind the mangroves, more or less following the high-tide line to a cleared area and large rock. Here a viewing platform takes advantage of views of
the creek and to enable marine organisms to be inspected at low tide.
Sign 3 Original inhabitants
From this point on there is frequent evidence in shell middens of the original Kuring-gai Aboriginal people. While this track gives the appearance of an amenity provided
by government authorities for the benefit of modern-day bushwalkers, it has probably been in use by humans since sea levels rose following the end of the last ice age thousands of years ago.
For an authoritative account of the indigenous people see section 2.2 ‘Aboriginal people of Berowra Valley’.
Berowra Creek to Calna Creek
As the track continues, the bushland on the right — mainly open-forest with Swamp Oak Casuarina Glauca and the occasional Grey Gum Eucalyptus punctata dominating — rises steeply towards Somerville Road.
Sign 4 All Creatures great and small
After the sign giving information on the animal species in the area there are a number of minor detours to avoid the high-tide line. Here and there large boulders have
tumbled down from the slopes above.
Sign 5 Catch the threats
At a major and particularly scenic bend in the stream the currents have so deepened the creek bed as to form a swimming hole and fishing place. The sign at this point
gives information about the catchment.
Sign 6 The Rock Club
After the sign dealing with the rocky places as habitats for plants and animals the track crosses several more shell middens.
Sign 7 Bush Supermarket
At the next sign grass trees Xanthorrhoea arborea are abundant. The sign explains the uses that the indigenous people and early settlers made of this plant.
Next, just after some stone steps — five down and three up — an old 1.5 m by 2 m concrete slab can be seen at the water’s edge. This was once a
landing stage serving the occupants of some fishing shacks formerly on the ridge above.
The track rises quite steeply, through open-forest thinning to woodland on the ridge. Near the top are the remnants of a sandstone wall embankment, built perhaps to
support a track between the landing stage and the shacks.
Sign 8 Stop! Look! Listen! And smell!
At the ridge-top is another shell midden. As locations selected by the indigenous people for the consumption of shellfish would have had some particular advantage, the
presence of a shell midden at this location, now hemmed in by trees, suggests that it might once have afforded a panoramic view of the two creeks, Berowra Creek below to the east and Calna Creek to the west.
An indistinct path crosses the main track at the interpretive sign, heading uphill to the right and following the ridge towards the hairpin bend on Somerville Road. About
40 m along it on the left are galvanised iron and wooden frame remains of one of the fishing shacks. Back on the main route, the steep descent is made easier by log-formed steps.
Sign 9 Rock ’n roll
Just before the last descent there is a seat and a sign explaining the geological and natural history of the Hornsby plateau, and of the earth. Calna Creek is just below,
and the steep cliffs of Gundah Ridge rise on the other side of it.
The twin logs bridging Calna Creek were dropped into place by an Australian Army helicopter when the Benowie walking track was formed in the 1980s. The 700 mm wide
boardwalk is most springy at the halfway point.
Calna Creek to Sams Creek
Calna Creek is fringed with mangroves at the log bridge. There is a walking track sign on the far side: the route to the right leads to Mt Kuring-gai (via Lyrebird Gully),
that to the left continues the Great North Walk towards Berowra. Go left for this walk.
Sign 10 Fragile marsh
Almost at once a salt marsh is reached, crossed by a boardwalk. Calna Creek salt marsh, once threatened by sand-mining proposals in Berowra Creek, is one of the few salt
marshes in the Sydney region not to have been filled in for sports fields, housing or industrial uses. It looks like an open paddock, yet it floods twice a day with each high tide; and at the spring and autumnal equinoxes it does
so to a considerable depth. Sea Rush Juncus kraussii, Bare Twig-rush Baumea juncea and Austral Seablite Suaeda australis dominate. The marsh is fringed by stands of Swamp Oak Casuarina glauca and River Mangroves. In time, if sea levels do not rise rapidly and siltation continues, this area might be colonised by shrubs and trees and could become a river flat forest. Already Casuarina glauca has established small islands in the marsh.
For a slightly longer walk, a 1 km extension beyond the interpretive signs at the salt marsh is recommended. This rocky and undulating segment is described in Walk 8,
Lyrebird Gully under the heading ‘Calna Creek to Sams Creek’. It is as attractive as the first section, and the big rock at Sams Creek is the highlight at the end.
The return to Crosslands 1.3 km from the salt marsh or 2.3 km from Sams Creek is likely to be much quicker than the outward walk. There are
barbecue facilities at Crosslands.