臺灣中新世之化石孢粉（VIII）──蕨類孢子與生物地層

Miocene Palynomorphs of Taiwan (VIII)–Pteridophytic spores and Biostratigraphy

臺灣北部中新世地層的蕨類孢子計有3綱，44形態屬，104種及變種，其中筆者等所立者計有9新種與3新記錄種。利用蕨類孢子分析臺灣北部苗栗出磺坑西翼，臺北三峽、基隆野柳之中新世地層採集的82個樣品，認定十個生物地層上重要事件，由諸事件，將臺灣北部中新世地層劃分為9個孢子帶。這些孢子帶與岩石地層單位間之對比顯示大致相符的現象。中新世地層單位蕨類孢子首次出現的種數，由老地層向新地層呈遂次下降的趨勢。由水蕨孢屬（Magnastriatites）在地層中量的變化，顯示桂竹林層與南莊層為較乾燥生態環境，觀音山砂岩段為沼澤極盛的生態環境，而下部則呈現潮濕與乾燥生態環境更替的現象。

The stratigraphic occurences of 3 classes, 44 form genera. 104 species and varieties of the Miocene fossil Pteridophytic spores from the sediments of the North Taiwan including the Miocene formations on the western flank of the Chuhuangkeng section of Miaoli-hsien, Keelung-Yehliu section and Taipei-Sanhsia section of Taipei-hsien were obtained. Nine new species and three new records were also proposed. The distributional range of these 104 pteridophytic spore taxa in 82 samples have been investigated, then ten useful biostratigraphy events can be recognized. Based on those ten events, the Miocene sediments of Taiwan can be subdivided into nine spore zones. These spore zones have a close correlation with rock units. The fossil sporomorphs which appeared at first time in rock units, decreased its numbers gradually from the oldest to youngest rock formations. From the amount of the Magnastriatites in the different rock units, the habitats of the youngest rock formations of Kueichulin and Nanchuang were dry, and the Kuanyinshan Sandstone was swamp and the older rock formations showed repeatedly alternative swamp and dry conditions.