This was one of the first trigs that I ever intentionally visited, back 1983, as it was only a few kilometres from where I lived.
There was no houses within 100m in those days.
The rhomboidal plaque on the Cook trig reads:
"Cook Trig Station is part of the early trigonometric
survey of the local area. It is an important landmark
and is one of the highest points in the district.
"The station forms part of a group
of thirty trigs stations in the Ku-ring-gai 'area'.
"Cook Trig Station is associated with four nearby
recovery points. Two of these are located adjacent to
the station, and two others are located about
thirty/forty metres away. The three recovery points on
the property are identified by plaques. The fourth
recovery point is located on the adjacent Crown Reserve.
1829
Land to the south of the Hawkesbury River,
including the Ku-ring-gai National Park, mapped by Surveyor
General Major Mitchell
1883
Cook Trig Station established with
a stone cairn and survey plug
from 1891
Residential development in north Wahroonga
1936
Stone cairn and vane renewed
1974
Concrete pillar erected over a Trig cover box
with new stainless steel survey plate installed above the Trig plug.
Four associated recovery points erected on site
1991
Storm damage causing mast and vanes to be removed
2000
Residential development of site
From the book by Tony Dawson, "Guide to the Historic Trigonometrical Stations of Sydney's North" (2007), "It should be noted, however, that the hill on which the trig stands was recognised as a place where a particular kind of butterfly mating behaviour, known as 'hill-topping', occurred and this contributed towards the significance of the site. Whether or not the butterflies survived the subsequent development as well as the trig is not known." p54
On the top of the trig is a "Direction Plate", pointing out x 4 localities, and three of the "Recovery Marks" for the trig. Being:
Terrey Hills: 67º 14(')
Baha'i Temple: 71º 14(')
Recovery Mark 202º 3.11m
Hornsby Heights: 313º
Recovery Mark 333º 4.12m
Recovery Mark 334º 31.70m
Berowra: 359º
From page 60, Official number: 1582
"Year FIRST placed: 1883
Lat/Long: S33º 41' 58" E151º 7' 35"
Height: 201 metres
Location: North Wahroonga"
From page 100:
"MGA Coordinates: Zone 56 Easting 326362 Northing 6269579
The trig is situated within a residential development at 153-164 Grosvenor Street, North Wahroonga about 100 metres north of Fisher Avenue. It is listed as a heritage item and comprises a concrete pillar bearing a commemorative plaque and a direction plate."
This can also be found as TP5563, on the GCA site at: (
visit link)
Revisited: Saturday, 9 January, 2016 (to take further photos)