This Review originally appeared in the June 2026 edition of “StoneSpeak”, the Newsletter of the Southland Geological and Lapidary Club. Below is a slightly expanded version. An Index to this Series of Reviews is here. The Southland Club’s website is here and its Facebook Page is here.
When I was looking for good introductory material about trace fossils three years ago, I came across an excellent article “Someone passed this way: Tracks, trails, impressions, and footprints” on the “Geological Digressions” website. I liked the turn of phrase used there: “Trace fossils are what is left of the activity of some ancient critter”. It turned out that the site is produced by a retired New Zealand geologist, Brian Ricketts.
Ricketts first studied geology at the University of Auckland in the early 1970s and did his doctoral degree in the Canadian Arctic. He then worked for the Geological Survey of Canada (GSC) for a few years. “I quit the GSC in 1997 and moved with my Canadian family back to Aotearoa–New Zealand to work a 4-year teaching stint at the University of Waikato.” But “with an evolving disenchantment of academia, I decided to form my own consulting company in 2005 – a company of one – and never looked back!” (quotes taken from “A Geological Life” on the website). During his time as a geologist, he also worked in Hungary, Chile, Australia, USA, the United Kingdom and the Netherlands. Retired now, Ricketts spends time on his Waikato organic kiwifruit orchard but also continues the development of “Geological Digressions”. More details on his background can be found in “A Geological Life”.
Ricketts started his website in December 2015. He states there that “I do this for the love of it. I do not receive any remuneration for the site (and I don’t advertise). The website is not attached or beholden to any organization.” The main part of the site is a “Virtual Classroom” containing material on sedimentology, stratigraphy, volcanology, geological structure, sedimentary basins, petrography and petrology – this is aimed primarily at university undergraduate students. There is a lot of material here – 23 Main Sections, each with numerous articles – and often useful links are made to other sources as well as related pages in “Geological Digressions”.
For example, in the Virtual Classroom Main Section “Minerology of Sandstones”, there are 20 articles, one of which is on “Bivalve morphology for sedimentologists”. It looks at bivalve fossils in detail, including their external and internal morphology, and shell orientation, with well-labelled illustrations. One of the other Main Sections is “Lithofacies”. Lithofacies refers to the physical and compositional characteristics of a sedimentary rock unit or sediment layer. There are 41 articles in the Section, one of them being “Ripple Lithofacies – Ubiquitous Bedforms”. It describes how ripples are formed on sedimentary surfaces and their different characteristics.
This “Virtual Classroom” is an excellent resource for people who have not formally studied geology – here you can get access to some of the material that is presented to university students. Yes, it can be technical, but it is well presented and a treasure for the keen learner.
Other articles in “Geological Digressions” are written with non-specialist or non-technical people in mind. Across the top of the site’s pages are links to four groups of articles: Glossary, Atlas of Sediments, Ancient Earth, and More. There are 11 glossaries (alphabetical lists of technical terms with their meanings), on topics including Stratigraphy, Sedimentary Structures, Volcanics, and Palaeontology. Alongside the explanations of key terms are links to any website articles relevant to them. “Atlas of Sediments” is a collection of photos that Ricketts has accumulated. There are 24 groupings here. One of them, for example, is “Atlas of Trace Fossils” which has 33 photos of different trace fossils, some from New Zealand.
The “Ancient Earth” heading takes you to 13 articles. The second one asks how old the Earth is. Here, Ricketts looks at a number of people in history who have attempted answers. He then refers to the search for the oldest rocks on Earth and what they imply. Another “Ancient Earth” article is on stromatolites, the earliest physical life form on Earth. Under the “More” heading are 14 other topics, some of which contain a lot of different articles. For example, “Interpreting Earth” has 28 articles, ranging from how sand gets turned into stone to understanding how a fossil forest in the Arctic has survived.
As you can see, “Geological Digressions” is large, detailed, diverse and wide-ranging, containing both technical and non-technical geology-related information broadly defined. The Home Page refers to “436 articles” being there. In general, these are well-written and have lots of interesting detail and illustrations. You can use the “Search” function to look for something specific. Or you can take a stroll along its many corridors, exploring whatever takes your fancy.
The next Review in this Series is not yet available.
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