During this period, his research concentrated on the Lower Carboniferous floras of Scotland including those from the Pettycur Volcanics and the East Kirkton Quarry.
22.
The limestones, which date from the Visean stage of the Lower Carboniferous, formed as sediments in a tropical sea approximately 325 million years ago.
23.
A useful index fossil, this tree is found in strata dating from the Upper Devonian to Lower Carboniferous ( ), and has a global distribution.
24.
Next is " Carlloceras " from the Upper Devonian of North America, followed by " Diorugoceras " from the Lower Carboniferous of Europe.
25.
The Aipoceratidae include the Lower Carboniferous " Aipoceras " and " Asymptoceras ", and " Librovitschiceras " from the Upper Carboniferous.
26.
The local bedrock consists of the Cuyahoga Formation ( shale ) and the overlying Logan Formation ( sandstone and conglomerate ), both Lower Carboniferous and rich in fossils.
27.
The lower Carboniferous has a flysch facies along the southern boundary of the zone, and also in the San Vitero area and around the Morais and Bragan�a Massifs.
28.
The term, the'Pennine Block-and-basin Province'is frequently used in literature to describe the situation which prevailed particularly during the lower Carboniferous.
29.
Only in the western Pyrenees is the Lower Carboniferous ( Mississippian ) distinguished from the Devonian sediments by an unconformity, starting off marine with a transgressive quartz pebble bed.
30.
An example is the sandy beds near the end of the lower Carboniferous of the west of England ( the " Drybrook sandstone " of the Forest of Dean ).
