Title: Geology of the Shidaka Coal-Field in Kasa-gun, Kyoto Pregecture.,
Abstract: Little has been known of the stratigraphy of the Shidaka coal-bearing group, and its age has been a most question., The group can, however, now be readily classified and its age determined as late Triassic because Myophoria 6 spp., in addition to Gervilleia spp., Nucula? spp., and a few others were discovered in the Shidaka formation., It is thoutht to be younger than Carnic because the Carnic Nabae formation adjacent to Shidaka coal-field is strongly disturbed together with the older fromations, while the Shidaka-group lies with clino-unconformity on the disturbed Paleozoic formation and, cut by faults, forms a half-basin by itself., The clino-unconformity at the base of the group can be seen on the western margin of the basin., On the east side of the basin a limestone in the basement yields Neoschwagerina., The Shidaka-group, 1650 to 1720m thick, is composed of molasse-type sediments., The component formations are in descending order as follows: Shidaka formation-260 metres., Coal-bearing sandstone., Coal-bearing alternation of calcareous shale & sandstone., Conglomerate., Plants and shells locally present., Okadashimo formation-250-180 metres., Alternation of shale & sandstone., Conglomerate., Okadayuri formation-430 metres., Shale., Alternation of sandstone & conglomerate., Conglomerate Humuro formation-600 metres., Reddish or greenish sandstone & conglomerate., Alternation of fine conglomerate & sandstone., Reddish or greenish shale., Alternation of sandstone & conglomerate., Conglomerate., Hannyaji formation-180 metres., Alternation of fine conglomerate & sandston., Reddish or greenish sandy shale & shale., Conglomerate & sandstone.,