The causal mechanism producing the recent temperature rise at the earth surface is still not clear, though an increasing CO2 concentration is generally thought to be the driving force of recent global warming. An alternative hypothesis has been proposed that the driving force is due to a change of solar activity. In this short review, I describe the historical change of the surface temperature on the earth from the Precambrian to the present with reference to the CO2 concentration of the atmosphere. The survey of the spectacular history of the earth reveals that an increase of atmospheric CO2 pressure has a close relationship with the temperature of the earth during geologic time, but the causal and effect relationship between the two items is still not yet clear. Therefore, further scientific studies are needed before deciding whether global warming is caused by the increasing CO2 pressure due to fossil fuel consumption.

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Observation of outcrops of the Ayashi-Okubushi Monocline, western Sendai, indicates that the monocline is closely associated with thrusts. These thrusts also cut the Quaternary terrace deposits. Among these thrusts, the largest thrust is the north-northeast trending Ayashi Fault, known as an active fault. The thrust geometry indicates N-S and NW-SE compressions in late Quaternary time. The Ayashi-Okubushi Monocline crosscuts the older Kagitori-Ayashi Monocline.

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Many tephra beds are intercalated in the Plio-Pleistocene Uonuma Group in the Uonuma district in Niigata Prefecture, central Japan. Early Pleistocene tephrostratigraphy in the Lower and Middle Formations of the Uonuma Group dated 1.75-1.15Ma is established by using their lithofacies, petroghaphic properties and chemichal composition of glass shards. Accordingly, the following things are newly cleared:"Tmt1","Tmt7","Tmt8","Tmt12","Tmt13","Tmt14","Tmt15","Tmt16" and "Tmt18" Tephra beds are correlated to Tzc, Kaj (newly defined), Nss, SK090, Uoc, Mgp, SK075, Hop and Hkp tephra beds. At least 31 early Pleistocene tephra beds are intercalated about every 20,000 years in this horizon.

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Extension joints with a peculiar shape of hemispherical lens were observed in the Narukawa Andesite, Nanae, Hokkaido. The size of the joints ranges from 5 to 46cm in diameter and from 0.7 to 2.4cm in depth. The occurrence of the hemispherical joints is restricted on the surface of platy and/or columnarjoints of the andesite lavas. The joint surface morphology is characterized by a plumose pattern, which is distinctive at the joint fringes. The hackle marks are also common around plagioclase megacrysts, which can be observed on the bottom of the hemispherical lenses. In some cases the jointing stays on the half ways, where the lenses remain on the platy surface of lavas. Taking all the modes of occurrence into considerations, the hemispherical lens-shaped joints are explained as extensional cracks initiated by a residual strain within individually jointed blocks of plates and/or columns in the andesite lavas.

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