虫形弓笔石和离心弓笔石的变异范围
傅力浦,王健,孟永,张子福,王欣,张举
摘要(Abstract)：
<正>自从国际地层委员会对温洛克统底界再研究以来,在中国紫阳地区找到了许多横过兰多维统至温洛克统的连续剖面,随着调查和研究的深入,必然提出许多新的问题提供给大家讨论。根据Lenz和Melchin的意见,温洛克统底界之下的关键笔石C.insectus的特征在于它的巨大尺寸,多次分支,主枝上在幼枝发生前部分的强烈缠绕。它与C.murchison的区别在更宽阔分散的幼枝,也以此与C.margusaricus(Golikov)不同。但这些区别它们在定量上是多少,笔者根据世界上7个地点的统计,这个幼枝间隔的幅度是10~68个胞管或毫米,第一与第二
关键词(KeyWords)： 生物地层学;笔石;弓笔石;志留纪;紫阳;陕西
基金项目(Foundation):
作者(Author): 傅力浦,王健,孟永,张子福,王欣,张举
DOI: 10.19839/j.cnki.dcxzz.2013.04.065
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