ABSTRACT

The “Coteaux du Pont Barré” in Beaulieu-sur-Layon is a Regional Natural Reserve which is home to exceptional flora and fauna. Recently fossil plants have been discovered at the site adding to its natural heritage significance. The exposure which is part of the “Sillon Houiller de la Basse-Loire” contains Serpukhovian-age (330–320 Ma) remains of sphenophytes, ferns, and lyginopteridopsid and cycadopsid pteridosperms, which are described for the first time as well as the geology of the site. Most Carboniferous macroflora previously described from the Maine-et-Loire has been based on ex situ specimens from now abandoned and inaccessible coal mines. The newly described macroflora shows evidence of in situ remains and differs somewhat in composition from those reported from the coal workings, especially in the total absence of lycopsids and Calymmotheca pteridosperms, and instead having abundant medullosalean foliage (Neuralethopteris). The co-occurrence of Sphenopteris elegans and Neuralethopteris densifolia suggests a slightly younger age compared to the macrofloras documented from the coal-bearing deposits. However, this could be an ecological consequence of the flora growing in better-drained substrate habitats.

摘要

莱永河畔博利厄的“Coteaux du Pont Barré”是一个区域自然保护区，拥有独特的动植物群。最近在该地点发现了植物化石，增加了其自然遗产的重要性。“Sillon Houiller de la Basse-Loire”的暴露部分包含谢尔普霍夫时代（330-320 Ma）的蝶类植物、蕨类植物、铜蕨类和苏铁蕨类蕨类植物的遗骸，这些都是首次被描述以及地质学网站的。此前在缅因-卢瓦尔省描述的大多数石炭纪大型植物区系都是基于来自现已废弃和难以进入的煤矿的易地标本。新描述的大植物区系显示了原位的证据仍然存在，并且在成分上与煤矿报道的有所不同，特别是完全没有石松类和蜡萼蕨类植物，而是具有丰富的髓叶（Neuralethopteris）。秀丽隐杆线虫（Sphenopteris elegans ）和密叶神经蕨（Neuralethopteris densifolia）的共生表明，与含煤矿床记录的大型植物群相比，它们的年龄略年轻。然而，这可能是植物群生长在排水更好的基质栖息地的生态后果。