The significance of a thin coal within the open water facies association depends on its origin: given its discontinuous nature and lack of underlying roots, it likely represents organic material (vitrain) resulting from coalification of a transported lycopsid
log rather than an in-situ histosol (peat).
The outer regions of stems (e.g., of arborescent lycopsids
, calamites, cordaites), to which root climbers may have been attached, are often not well preserved, and the climbers may have been separated from the stems during fossilization and/ or diagenesis.
By mid-August, Don and Lucy turned east to meet up with the others, who had just discovered tetrapod remains in upright lycopsid
tree stumps near Florence, on the northeastern side of the island (Fig.
Evolutionary-developmental change in the growth architecture of fossil rhizomorphic lycopsids
: Scenarios constructed on cladistic foundations.
Specimens belonging to the lycopsid
genus Bothrodendron are identified by distinctive shoots that have small superficial leaf scars.
Diversity changes in lycopsid
and aquatic fern megaspores through geologic time.
A drowned lycopsid
forest above the Mahoning coal (Conemaugh Group, Upper Pennsylvanian) in eastern Ohio, USA.
For the first time, it became clear that coal originated as a peaty soil beneath a lycopsid
forest, rather than as a transported log jam--a hypothesis earlier favoured by Lyell (1830-33).
The first convincing argument for the terrestrial origin of coal had come from Logan's observations (1841) that Stigmaria were the roots of lycopsid
trees in their original position of growth.
Having personally witnessed a 25-foot-tall standing lycopsid
trunk and discovering that Gesner once measured one 40 feet tall (Lyell 1842; Wilson 1998), Lyell wrote to his sister that the Joggins fossil forests were "the most wonderful phenomenon perhaps that I have ever seen" (30 July 1842, in K.M.
134), which yielded structurally preserved lycopsid
and cordaitalean axes.
plants predominate in the basal limestones, whereas overlying siltstones and sandstones contain a mixed suite of drifted gymnosperms (cordaitaleans), sphenopsids (primarily calamiteans), pteridosperms and putative progymnosperms (Falcon-Lang 2003a).