Environmental Engineering Reference
In-Depth Information
The environmental conditions of the Namurian continued into the latter part of the Carboniferous
period, with the formation of the Coal Measures. The coal seams originated as peat formed in low-lying
swamps on the coastal plains, and coal formation may be linked to changes in sea level. The Coal Meas-
ures consist of sandstones, shales and coals arranged in a repeated sequence, indicating that forests grew,
were buried by shales as the land subsided and then by sands as the rivers deposited sediments. On top of
the river sand soil developed and eventually the forest became established again. In the northeast of the
peninsula coal occurs in seams running diagonally from Blackpill to Llanrhidian.
The freshwater and brackish swamps, marshes and lagoons of this period of Gower's history suppor-
ted rich forests and there were large numbers of fern-like plants, the seed ferns, together with the true
ferns that occur today. One of the most conspicuous features of the flora at this time was the presence of
large tree-sized ferns in groups that are now only represented by small herbaceous types, the most spec-
tacular being the horsetails and lycopods. Such plants inevitably broke up and fossil fragments consisting
of discrete pieces of roots, stem and leaves are common.
ThegreatcoalfieldbasindominatesthegeologyofSouthWalesandGowerformspartofthesouthern
rim of the massive South Wales Coalfield syncline. The peninsula should therefore consist of strata that
