For some general information, including some maps, about the Campanian St. Bartholomä-formation in Styria, Austria see:
The rudist-bearing St. Bartholomä-formation covers an area of about 3km2. Within this area, there are a few sweet spots, where rudist can be found with some confidence: one of the creeks west of Kalchberg; a pile of rocks west of Kalchberg, collected during ce
Now the sandstone slab behind the red x (last photo of the previous entry) has been removed. Can you spot it, just above the pocket knife? Photo taken 09/13/2018.
Closest! There was a large rudist just behind the sandstone slab, lying in a depth of about 40 cm below the surface of the scree slope. Still in situ, only some roots and small stones removed for the photo. Pocket knife is 9 cm long, some tapering of the rudist is clearly visible. Such a nice
Fine, a very nice rudist - a Hippurites nabresinensis -, one of the longest I have found so far in St. Bartholomä (18 cm). But it came even better! At home, I recognized that I have already seen a quite similar traverse fracture before. Indeed, here it is, with the cleaned traverse fracture of the newly found rudist below. Maximum diameter is about 7.5 cm.
The two parts fit together (considering that there are at least 100 years of weathering between them), resulting in t
Here are the numbers I promised :
From 07/16/2017 to 09/13/2018, about 140 hippuridit rudist specimens were found in the scree slope of "Point 25", the sweetest of all spots in St. Bartholomä. The species distribution is (approximate numbers, with examples):
Hippurites colliciatus: 80 (with 140 individuals – many pseudocolonies!) - F, G, H, J
Hippurites nabresinensis: 10 - I and possibly K
Vaccinites vesiculosus: 25 - A, B
Vaccinites alpinus: 10 - C
Vaccinites cf. s