Reply to discussion of ‘Gisbornian (Caradoc) graptolites from New South Wales, Australia: systematics, biostratigraphy and evolution’ by B. Rickards, L. Sherwin and P. Williamson

✍ Scribed by Barrie Rickards; Lawrence Sherwin; Penelope L. Williamson

• Publisher: John Wiley and Sons
• Year: 2003
• Tongue: English
• Weight: 54 KB
• Volume: 38
• Category: Article
• ISSN: 0072-1050
• DOI: 10.1002/gj.951

✦ Synopsis

VandenBerg (2002)

and in his Discussion paper (2003, this issue of Geological Journal) raises doubts on our attribution of the Keenan's Bridge (near Cheeseman's Creek, NSW) graptolite fauna to the Late Gisbornian (Rickards et al. 2001), preferring to refer the assemblage to the Bolindian, and at the same time he re-identifies several of the species we recorded. There is nothing wrong in principle in doing this, but it seems to us that it would have been a more convincing revision had our collections been re-examined and had full systematic (re)description been given. Secondly, by way of introduction we would register our surprise that VandenBerg has published in a form which gave us no immediate right of reply and left us with no option but to seek publication elsewhere and at a much later date. His comments follow a pre ´cis of our paper, omitting the detailed evidence (see VandenBerg 2002). The crux of the problem, as VandenBerg rightly says in the third paragraph of his Discussion paper, is our identification of Climacograptus bicornis J. Hall (1847), and his identification of the same specimens as Appendispinograptus longispinus (T.S. Hall, 1902). If our material could be proved referable to the latter then, indeed, a Bolindian age for the fauna would be indicated.

Let us first deal with the three 'points of difference' between the two, as listed by VandenBerg (2002, p. 7).