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400 Million years in 4 hours The small-scale geology of Austria makes it possible to observe and collect invertebrate marine fossils from a time span of nearly 400 Million years (Ma) within a few hours and at a distance of only about 10 km: - 395 Ma old Devonian (Eifelian) corals - Ölberg - 80 Ma old Cretaceous (Campanian) rudists – St. Bartholomä - 12 Ma old Miocene (Serravallian/Sarmatian) gastropods - Waldhof I did this special hunting trip west of Graz at October 22, 2019 as a "feasibility study". The youngest and oldest fossils can simply be picked from the ground (or photographed); the “middle-agers” require some searching; I succeeded to find a few good specimens within one hour. Weather was perfect with nearly 25°C (!). Simplified geological map of Styria with the visited area west of Graz (red rectangle). Geological map of the visited area (1:50.000), composed of two adjoining map sheets. Red numbers denote visited fossil sites (and their age in Million years). Note the fossil sign in the blue formation in the upper middle of the map. This is the upper Devonian Steinberg-formation with goniatites. These fossils are not abundant, though, so I have never explored this hill… Topo map of the area. Red numbers denote fossil sites, A and B are sites of landscape pics. Just to show off some landscape: View from point “A” in Steinberg towards west. K = Kreuzegg mountain (570 m, Campanian St. Bartholomä-formation) at a distance of ca. 5 km. A = Plateau-like Amering mountain (2187 m, high-grade metamorphic rocks) at a distance of ca. 40 km. View from point “B” at Kreuzegg mountain towards north to southeast. Pano composed of 4 individual pics, spanning about 140°. Labeled mountains and hills in the background are: S = Schöckl (1445 m, Devonian epimetamorphic limestone) at a distance of ca. 20 km. P = Plabutsch mountain (754 m, namesake of the fossil-rich Eifelian Plabutsch-formation) and B = Buchkogel mountain (656 m), both at distance of ca. 10 km and located immediately to the west of Graz. Ölberg and Waldhof sites are between P and B, but not visible. Note the about 1000 m high, largely deforested mountains at the left side of the pano (Mühlberg, Pleschkogel etc., lower Devonian, dolomitic Flösserkogel-formation). The severe deforestation of these hills is due to a strong storm in 2008 (“Paula”). Continued...

Chonetid impressions in slate (“Chonetenschiefer”) from the Plabutsch-formation, Palaeozoic of Graz, Styria, Austria (Devonian – Eifelian) The classic occurrence at Gaisbergsattel, west of Graz The Eifelian Plabutsch-formation – mostly fossiliferous limestones – of the Palaeozoic of Graz, Styria, Austria, contains locally beds of slates of various colors. Some of these beds contain abundant limonitic imprints of brachiopods and bivalves (“Chonetenschiefer”). The locality first mentioned in the literature (1871) is that at Gaisbergsattel west of Graz: Austrian map with "classic" occurrence of “Chonetenschiefer” at Gaisbergsattel (red x). Part of geological map of Kuntschnig (1937) with “Chonetenschiefer” between the two red x east of Gaisbergsattel. Here, the slate layer is up to 2 m thick, grey like mice and splits easily in flat pieces (Hanselmayer, 1957). The fauna was first listed in Heritsch (1935): Chonetes subquadrata Chonetes sarcinulata Chonetes oblonga Chonetes nova species (most abundant!) Spirifer aculeatus Pterinea fasciculata Pterinea cf. bifida Pterinea cf. costata More than 10 years ago, my first attempt looking for these rocks was not successful. A few days ago (03/29/2019), however, I stumbled over this rock by pure serendipity. A small piece of it was lying on a rather busy hiking trail (“Mariazeller Weg 06”) east of Gaisbergsattel. Relief map with my first find of “Chonetenschiefer” at the hiking trail (red x) and supposed outcrop area of this rock after the geologic map of Kuntschnig (1937). Hiking trail “Mariazeller Weg 06”, where I found my first specimen. Pic from 04/01/2019. I was able to split the rock with my fingernail – and there they were, the limonitic brachiopod imprints! A faint radial ripping is visible. No other specimen was found on the trail. Now I looked closely at the geologic map, the text of Hanselmayer (1957), and the relief map and decided to explore the area around the red line (see above), where the outcrop of this rock is supposed to be. It’s a forested area with dense undergrowth, among the undergrowth many spiky blackberry bushes… No outcrop was found, but fallen trees have exposed some rock fragments: Abundant limestones, light brownish slates and, yes, some grey slate, mostly small pieces. I split only the largest of them – and again some brachiopod imprints were found...

Supplementing the post in “Fossil Hunting Trips” about the Devonian Plabutsch-formation in Styria, Austria (with some background info): http://www.thefossilforum.com/index.php?/topic/90431-some-fossil-hunting-in-the-plabutsch-formation-of-the-palaeozoic-of-graz-styria-austria-devonian-–-eifelian/ I would like to post some more fossil specimens in this thread. More specimens will follow from time to time (hopefully). The first two specimens contain abundant branches of the tabulate coral Striatopora? suessi. Field pics of these specimens are already posted in the hunting trip, but here you can see also their side views, showing the alingment of the individual coral branches. (I don´t know why pics don´t look good here, but if you are zooming in, they are ok).

As there are some polished fossil-rock specimens from this formation in the Christmas auction, I would like to present some background info with (mostly) some field photographs, so I have put this in “Fossil Hunting Trips”. The Palaeozoic of Graz is a thrust sheet within the Eastern Alps, composed of Silurian to Pennsylvanian sediments. It consists of three separate nappes, the most fossiliferous formation is the Plabutsch-formation within the Rannach nappe. This Devonian formation is of Eifelian age (ca. 395 Ma), about 100 m thick and mostly made up of a very dark, gray-blueish to black, fine-grained, thickly bedded limestone. Superficially, it weathers to a medium to light grey color. Geological map of Styria with the Palaeozoic of Graz situated north of Graz. Stratigraphic column of the Rannach nappe of the Palaeozoic of Graz, Plabutsch-formation is Nr. 4. From Hubmann & Gross, 2015. Thicknesses of formations are not to scale! The Plabutsch-formation crops out at various places to the west and north of Graz and more than 100 fossil sites are known within this formation. The most abundant fossils are corals, brachiopods, stromatoporids and crinoid fragments. Other fossils like gastropods, bivalves or trilo-bits are very rare. In a paper from 1975, about 50 coral species are listed, but less than 10 are abundant: Tabulata: Favosites styriacus Penecke, 1894 Pachycanalicula barrandei (Penecke, 1887) Thamnopora boloniensis (Gosselet, 1877) Thamnopora reticulata (Blainville, 1830) Striatiopora? suessi Penecke, 1894 Rugosa: Thamnophyllum stachei Penecke, 1894 Zelophyllia cornuvaccinum (Penecke, 1894) Do you feel that there is something strange with this list? Yes, it is! Most species have their type locality within this formation and were first described by Penecke, except T. boloniensis (T. reticulata was also erected by Penecke as Pachypora orthostachys and later synonymized with an earlier described species). In my opinion, this does not reflect a high degree of endemism, but an urgent need for revision… The most abundant fossil is Favosites styriacus, which can form massive colonies up to 0.5 m in size. Here is an example from Hohe Rannach Mt. (1018 m) north of Graz, photo 05/26/2018, Col-Nr. 4093, length of pocket knife is 9 cm: As most fossils in this formation, it was found in scree and float in a wooded area. Nr. 4093 is waiting near the pocket knife toward the lower right corner… Another Favosites styriacus, north of Fürstenstand Mt. (754 m), northwest of Graz, photo 10/30/2015, not in collection. Tabulae are very well visible, weathering is usually your friend there!