Commenced May 2009:  Any contribution/discussion is welcome:

Please contact the author at ~~ john.mail "@" ozemail.com.au

 

 

This is a PROJECT PAST small project

 

 

 

The potential role or place of "lookout" rocks

as instructive points in thinking about

the past

 

 

( ~~ PART OF THINKING LIKE/ABOUT A ROCK, MOUNTAIN, FOSSIL ? ~~ )

 

Learning to think about rocks and

the passage of time, using as an

example a Blue Mountains rock

called 'THE ROCK'. 

 

 

 

( This rock of no-name rock, or no official name, is a popular tourist rock, place for wedding party photography

and former domicile of the 'Unknown German, supposed enemy alien.   Also known by a number of apparent misnomers like 'Sunset Rock' it is located at Little Switzerland Drive.  )

 

" This Table Land is extremely beautiful and has very fine Picturesque grand scenery -- consisting of deep finely wooded Glens,

stupendous Rocks & Cliffs, with high distant Hills and Mountains."   (So said Governor Lachlan Macquarie, April 1815).

 [Photo:  SCRAE Photographic Art, Wedding Photography, Katoomba]

 

 

It is thought the Governor's party of inspection of 1815, following the building of Cox's first road across the mountains, may have come to somewhere in this vicinity (or somewhere closer to the nearby falls).   Perhaps more certainly, the explorers of the Blaxland party in 1813 probably reached here, the western edge of the Kings Tableland, as their first great vista of what people call today the famous Blue Mountains tourist visitors - today constantly visited by thousands of visitors.

 

For further records (as so far found) of just what the Governor wrote, or just what the explorers recorded in their journeys, see the link

"More about The Rock" at the bottom of this page.

 

The 'one rock' theme of this webpage (part of 'Project Past' about perception and interpretation method for the past) is about what can you get from visiting just one rock.

 

What are the ways of thinking about 'a rock' - in this case using the category of 'lookout rocks'.

 

On the old adage  that all things can be divided in three (father, son and the holy ghost - endless other examples), one might say there are basically three directions of thought on or upon something like 'The Rock'.

 

* It's well known that wild natural rugged places may inspire inwards thoughts in some.

 

* Of the outward-directed thinking there's the "looking down" sort.   At one's feet is the immediate sandstone of 'The Rock'.   How did it form depositionally, and how did its various latter-day (post-erosional) features form?    Then looking further down there is the vast Jamison Valley.   What is down there?    Another vast array of things geological and representing an assortment of times long in  the past.

 

* And thirdly there's the "looking laterally" type thinking.   This rapidly can lead, on the Blue Mountains, to thoughts of 'which layer is which' from one cliff face to another.    This is called, in geology, the process of strata CORRELATION.

 

Re correlation, refer to the below two photos of the cliffs (Kedumba Walls) of Kings Tableland and Banks Wall in the Grose Valley.  Where is the 'Wedding Rock layer' on the latter cliff face (which continues up higher stratigraphically to a little bit of the basal Hawkesbury Sandstone before being capped by a basalt flow remant?

 

 

 

Kings Tableland cliff face, showing the 'Wedding Rock' (A) at upper left, the sandstone at "C" near the communication towers which may be the Kings Table unit, and the lateral extent of the Wedding Rock sandstone unit.  The Wedding Rock unit is weathered back a little way form the main vertical cliffs and separated presumably by some shaley interbeds.   Slightly shaley or interbedded intervals are reflected by the tree lines on the cliff face.   Note thinner bedded or interbedded sequence exposures at the medial tree line on the vertical cliff face below both "A" and "C" points.   (Photo:  Steve Bennett).   The two tree lines presumably correspond to the units known as the the Wentworth Falls Claystone Member (below Wedding Rock sandstone unit and just above the edge of the main drop) and the Mount York Claystone (about half way down the cliff face).   The sandstone above the  Mount York Claystone is the Banks Wall Sandstone.

 

Looking across the Grose Valley to Banks Wall, from Perrys Lookdown near Evans Lookout.   Blue Mountains, NSW.

Which of the three prominent tree lines (claystone or less massive sandstone/interbeds intervals) on Banks Wall

is the Wentworth Falls Claystone that underlies the 'Wedding Rock' unit?   Current thought is that the correlation

is to the first-down prominent trees line, the one with a big rock fall (white scar) at its right hand end.

 

 

An simple example of correlation by sighting.   The Three Sisters are remnant of the Banks Wall Sandstone

above the Mount York Claystone (main horizontal tree line).   The Kedumba Walls edge of the 

Kings Tableland is seen in the distance, with the 'Wedding Rock unit' the top sandstone

and the tree line below that being the Wentworth Falls Claystone Member.

 

 

HOW TO FIND 'THE ROCK' discussed here:  "Heading west up the mountain again, make sure you take the left turn at the Pot Shop onto Kings Tablelands Road. Then take a right turn a few kilometres further on along Hordern Road, followed by a left at the T-section. The road is dirt here, but start looking to find a park because you've arrived. You'll see a well-worn path onto the sandstone escarpment, before being captivated by some of the best views in the mountains. And the best thing? There are no signs to get here, so you'll never have to share it with 1000 other humans (which can't be said for the Three Sisters later on). I told you I'd give you some local knowledge. Soak up the views, they're quite inspiring" (by Pat Callinan in "The insider's guide to the Mountains", NRMA).

 

 

 

View from above.   A tourist bus at The Rock.   (Google Earth) 

This rock seems to have no formal name.   It is sometimes referred to as the Wedding Rock, or by various other names including Sunset Rock and Evans Lookout.  As shown herein, 'Sunset Rock' and 'Evans Lookout' are misnomers.  An early tourist map/guide is thought to have misidentified this rock as Sunset Rock, this being the possible source of the misnaming of it as such (which misnomer still lives on).   The most frequently used local name for it has possibly been simoly 'The Rock'.  As a prominent place and good lookout point, it seems possible some of the early explorers might have been in this vicinity after they reached Kings Tableland.

 

Blue Mountains regional map showing the western wall (called Kedumba Walls) of the Kings Tableland,

overlooking the Jamison Valley.

 

Enlargement around Wentworth Falls.  In the lower right corner, Little Switzerland Drive

(here unnamed) is the N-S dirt road to the west off "HORDEN RD".  

 

 

Diagrammatic 3D sketch of the same.   Wentworth Falls is the falls of Jamison Creek over the point where two

major eeasterly northerly trends of cliff line meet.   A popular cliff ledge walk, the National Pass, runs along

the easterly trending cliff.   The erosion of the falls forms a semi-circular cross-section 'embayment' that

has a step at the junction of the two main sandstone units.  Thus two separated vertical drops

comprise the falls.   The walk down along Jamison Creek from near Wentworth Falls station

has been named Darwin Walk to commemorate Darwin's visit here.

 

 

Prominent rock exposures - Aerial interpretation (A and B have been visited, C and D not yet visited).

A = "Wedding Rock"; B = Kings Table rock outcrop (Aboriginal habitation traces); C= rock

outcrops near the communication towers, assumed to be same unit as B; D = ditto, 

the track seeming to go only to a vantage point lookout.   What is at the end

of the road at D is currently unknown.

 

 

A tourist at the lookout rock.    (Photo:  "Near the edge", taken by tourists

Nick & Margaret Houston on their Sydney 11-18th March 2009 trip.  

 

Another tourist gingerly looks over the edge.  (Photo:  Takuya3110)

A wedding party at the edge.

 

Late/post-diagenetic features - ironstone bandings, sometimes forming closed ellipsoids.

 

 

DEEP TIME AND SHALLOW TIME

 

Looking at/from 'The Rock' deep time is the stuff down the bottom of the valley.  And the stuff of shallow time is the scratching of initials and grooves atop the rock, the rocks innumerable visitors (some of who come back year after year according to dates they have scratched), and a 'domicile' someone (the so-far little-known-about reputed enemy alien) built in a cave under the rock.

 

 

View of cliff face under the more massive bed, showing irregular erosion, presumably by both wind and water.

 

 

Around southern face of the above photo the rock is undermined by this large 'cave' which someone (the "German")

formerly commenced to enclose with a stone and concrete wall.   One story current about the construction within

the cave is that it was done by an 'enemy alien' (German) man fearing internment, in WWII year.

 

 

FORMATION NAMES

 

 

 

 

 

Bembrick C. S. and Holland W.N., 1972.  Stratigraphy and structure of Grose Sandstone in the Blue Mountains.

Quarterly Notes of the Geological Survey of New South Wales.

 

Bemrick was with the Geological Survey and Holland was at that time a research student in the Department of Geography at University of Sydney.   Holland mapped and named the Wentworth Falls Claystone.   He at that time had in preparation a thesis "New facts on the Narrabeen Group in  the Blue Mountains".

 

 

A marked change in the dip direction of cross bedding was discovered above and below the Wentworth Falls Claystone Member, as shown above.  Averaged cross-bedding azimuth for the underlying Burra-Moko Head Sandstone is similarly to the SE at 155 deg Mag (Bembrick, Bulletin 26, p.149).

 

Characteristically the claystone is overlain by a 4.5-6m thickness of conglomeratic sandstone with large well rounded quartz pebbles.   Cited examples of this are seen in quarries in Narrow Neck (cf. Patterson's quarry, QR142, MR03944) and and at Connaught Road, Blackheath [see also reported white quartz pebble gravel pit at Main Road, Katoomba; and Medlow Bath operation by G. Anderson which was partly worked by underground room and pillar method, MR 03920].    The Connaught Road quarry referred to in the 1972 QN is the Council quarry, on the north side of Govett's Leap Road one mile ENE of Blackheath railway station.   About 20 ft of fine quartz pebble gravel (half inch pebbles) was worked there.  The Anderson's quarry, on the east side of the highway 0.75 mile north of Medlow Bath railway station also worked about 20ft of gravel, covered by 'sand'.   This may be deep weathering of the sandstone and poor exposures suggest some very minor occurrences of similar material at Kings Tableland also.   Pockets of clean white sand also 

occur at the top of Nellie's Glen, 1 mile WNW of Katoomba railway station.   Such sites warrant a visit with regard to possible correlations.

 

A pellet claystone, with composition and texture like the Garie Formation claystone, overlies that coarse unit in the vicinity of Banks Wall [cf. 7ft claystone bed at Govetts Leap quarry (GR 293445) which has abundant 1/16th in pellets that readily weather out of the rock - GS1978/296].   At Sublime Point the Wentworth Falls Claystone Member is a 20ft zone of no outcrop down about 145ft from the top, with some buff and mottled chocolate claystone scree (GS1978/296).    

 

 

 

REFERENCES

Andrews, E.C., 1911.  Geographical unity of Eastern Australia in Late and Post Tertiary Time, with application to biological problems. Journal of Proceedings Royal Society of New South Wales.  Vol. 44, pp.  420-480.

Blaxland, Gregory (1778-1853), 1813 (Edited by Frank Walker).  A journal of a tour of discovery across the Blue mountains, New South Wales, in the year 1813 / by Gregory Blaxland, with references and explanatory notes, maps, etc. by Frank Walker.   [Copies at State Library]

Darwin, Charles.   A Naturalist's Voyage Round the World.  Journal of Researches  into the Natural History and Geology of the countries visited during the voyage round the world of H.M.S. Beagle under the command of Captain Fitz Roy, R.N. with illustrations by R. T. Pritchett of places visited and objects described.   [HTML version].

Goodwin, Robert Henry, 1968.   Studies in stratigraphy and sedimentation in the Blue Labyrinth, New South Wales.   M.Sc. thesis, University of New South Wales.

Young, R.W., 1978.  The study of landform evolution in the Sydney region: a review.  Australian Geographer.  Vol. 14, issue 2, pp. 71-93.

 

For further reading and consideration about this place see:   More about 'The Rock'