Lungfish, or dipnoans, have a history spanning over 400 million years and are the closest living sister taxon to the tetrapods. Most Devonian lungfish had heavily ossified endoskeletons, whereas most Mesozoic and Cenozoic lungfish had largely cartilaginous endoskeletons and are usually known only from isolated tooth plates or disarticulated bone fragments. There is thus a substantial temporal a...

The rarity of Devonian tetrapods and the absence of tetrapods during the first 14 million years of the Mississippian (Romer’s Gap) have inspired hypotheses of fish-tetrapod evolutionary transition as an escape from difficult habitats such as deserts or stagnant waters. These hypotheses and Romer’s Gap are tested here using depth to calcic horizon in paleosols of the northern Appalachians as a p...

Introduction There are three major oil sand areas in Canada, all in Alberta. There is also an oil sand deposit on Melville Island in the Arctic. The three major oil sand areas are from highest to lowest volume of reserves-in-place (AEUB 2003) Athabasca, Cold Lake and Peace River oil sand areas notwithstanding that bitumen reserves are also evident in subcropping carbonate rocks in Athabasca and...