Dalskardtjern- a Fossil Locality on Stord, West Norway
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NOTES- NOTISER Dalskardtjern- a fossil locality on Stord, west Norway HARALD BREIVIK Breivik, H.: Dalskardtjem - a fossil locality on Stord, west Norway. Norsk Geologisk Tidsskrift, Vol. 55, pp. 297-298. Oslo 1975. A small outcrop of fossiliferous Upper Ordovician Limestone and Shale is described from Stord, west Norway. New collections of corals support the previous suggestion that the rocks present are equivalent to Stage Sa in the Oslo Region. H. Breivik, 5419 Fitjar, Norway. Dalskardtjern, a little known locality on Stord, was first discovered in 1937 by Kvale (1938). In 1973 the author re-collected from the area and this note briefly describes the area and lists the fossils collected from Dalskardtjern. Dalskardtjern is situated about 3 km north of LitlabØ gruver on Stord (59.50 N, 5.22 E) western Norway (Fig. 1) and Iies at an altitude of ap proximately 245 m above sea level. Evidence from fossils found by K vale (1937:13-14) led him to believe that the rocks were equivalent to Stage Sa (Upper Ordovician) in the Oslo Region. The fossiliferous beds crop out at the eastern end of the small lake, Dalskardtjern, and cover an area 150 m in length and a maximum width of 30 m. The beds appear to form part of an anticline which Iies between gabbro to the north and a polymictic conglo merate to the south. However, the boundaries between them are hard to define because of the covering of moraine and vegetation. The area is crossed by a small ditch in the sides of which the fossiliferous beds are best seen. They again crop out in a southwesterly direction on the southem side of the lake; a small outcrop is seen on the north side of the lake as well. The rock type is dominantly a dark silty shale with a 3-5 m bed of lime stone between. The strike of the beds varies but is roughly NE-SW. The dips vary from being nearly horizontal on the north bank of the ditch to about 75° in a north-westerly direction on the southem bank. At the eastem end of the outcrop the dip is about 80° to the southeast. The axes of the small folds in the shale plunge slightly in the eastward direction of strike of the rocks. Fossils found by Kvale (1937) and identified by A. Monsen include Streptelasma europaeum, Reuschia aperta(?), fragments of a brachiopod (Orthis(?)), gastropod(?), trilobite and various crinoid ossicles. New collections made by the author in 1973-1974 include the following: Corals: Streptelasma primum (Wedekind 1927), Favosites sp., Catenipora sp. 298 NOTE SOm Fig. l. The distribution of the fossiliferous Upper Ordovician limestones and shales at Dalskardtjern, Stord. and Reuchia sp. trilobites: species of Brogniartella, Achatella, Hemiarges and fragment of a proetid. Other fossils include brachiopods of Stophomenid - an orthid-type, numerous crinoid ossicles, bryozoa and the alga Palaeporella. In all 270 fossils have been collected and show the following frequency: trilobites (40%), brachiopods (26 %), bryozoa (9 %), gastropods (7%); the remainer is made up of crinoid ossicles and other so-far unidentifiable frag ments. REFERENCE Kvale, A. 1938: Et kaledonsk effusiv- og intrusivfelt på Stord. Berg. Mus. Årbok 1937, 1-138. .