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Hawkesbury Sandstone deposited from a wall of water?

Today’s feedback comes from a W.N. of Australia who heard a CMI speaker describe the Hawkesbury Sandstone near Sydney, Australia.

Hawkesbury Sandstone forms steep cliffs along coast near Sydney.
Hawkesbury Sandstone forms steep cliffs along coast near Sydney.


A CMI speaker stated recently that Patrick Conaghan, geologist, has said that a wall of water 20 metres high and 250 kilometres wide had been involved in forming the Hawkesbury Sandstone. This is also stated in a CMI article on the subject, with the reference given: Bulletin of the Geological Survey of NSW 26:188–253.

I have tried to see if I can view the original article but so far am unsuccessful. I found one comment from a writer who said he had viewed the article and that no such reference to a wall of water is in it. There are numerous creationist site references repeating the claim of the wall of water, and one reference mentioning a newspaper piece of a wall of water 20 km [sic] high and 250 km wide!

There was and abstract I saw on “Dynamic Fluvial Basin for Sydney Basin” Journal of Geological Society of Australia 29:55–70 which gave no indication of such walls of water.

Are you able to state categorically that Patrick Conaghan did make such a statement? If not, will you withdraw or modify your article?

Yours sincerely,


Tas Walker responds:

You correctly note that CMI speakers and articles on the CMI website refer to geologist Patrick Conaghan saying that a wall of water 20 metres high and 250 kilometres wide had been involved in depositing the Hawkesbury Sandstone.

Conaghan was quoted as saying this in an article in the Sydney Morning Herald dated 30 April 1994 (pdf).

The newspaper article gives the reason why Conaghan came to this conclusion. It was his discovery of “fossilised sandstone ‘waves’ in cliffs above the Wolli Creek valley.” He said the waves were called recumbent cross-beds, which record the distortion of sediment layers by the massive flood current, and such fossil waves are found around the world. The waves at Wolli Creek were three metres tall, twice as large as any other known.

The other reason for Conaghan’s conclusion was that strata in the Hawkesbury Sandstone can be traced all the way across the 250-km width of the Sydney Basin. A map of the basin is included in the newspaper article.

I spoke to Patrick on the phone nearly ten years ago about what he said in the Sydney Moring Herald article. In our conversation Patrick described a particular portion of the Hawkesbury Sandstone where the strata were thick, structureless, and laterally continuous. He considered each thick layer would have been deposited almost instantaneously from a sediment-water mixture containing some 50–60% of sediment and travelling as much as 100 kilometres per hour.

My main purpose of contacting him was because I was answering a challenge from an article in the Australian Skeptic. I wanted to see if his discovery had been published in a geological journal. He said that it had not, that he was disappointed he had not published yet, and that organizational change and other activities at his university were preoccupying him. He did mention that he had written a geological section for the booklet The Story of Stone in the Wolli Creek Valley (George Morgan, Wolli Creek Preservation Society, 1994), in which he described the formation of Sydney sandstone and of Undercliffe ‘wave rock’ and its significance.

That partly explains why his reference to a wall of water 20 metres high is not in the geological literature. Even if he had published his findings, he likely would not make such a graphic statement in an academic geological article. I encouraged Patrick to work at getting something published because of the significance of his findings. I even thought I may be able to help him get started, or offer him the opportunity to publish in the Journal of Creation. However, his findings would be far more useful by being published in a secular journal.

So, in answer to your question, yes, Patrick Conaghan did make the statement and I have forwarded you a copy of the relevant article.


Tas Walker

Published: 29 July 2012

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