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Salt water intrusion in the Mekong River, Vietnam, was studied using a towing type echo-sounder (Model SC-3) and water quality meter (TPM CLOROTEC) observation instruments during spring tide of the low flow season in May, 2005. Observations were taken at two stations located at points 26 and 8km from the river mouth. Measurements were taken at hourly intervals for 24 hours during one week, using several instruments set on the river bottom. A joint towing observation system using echo-sounder and water quality meters has been proved its usefulness for analyzing the time-space behavior of salt intrusion in the Mekong River. Precise measurements of tide-related phenomena including water level, bottom currents and water quality (temperature, salinity, turbidity and chlorophyll-a) at two stations revealed detailed movements of the saline water-mass.

Salt water intrusion in the Mekong River has been studied using a newly-developed acoustic reflection profiling system (Model SC-3). This system determines the spatial distribution of the halocline by measurements of water quality, especially of salinity. This system was made by improvement of a 200kHz precision echo sounder. In the intermediate flow seasons of Dec., 2000 and Jan., 2002, salt water was present only downstream of the mound at 8km in ebb tide, but progressed upstream beyond the mound at 14km toward flood tide. A typical wedge-like profile was obtained at the observation toward flood tide on 28 Dec., 2000. Time series echo-sounding profiles obtained from ebb tide toward rising tide on 2 and 4 Jan., 2002 at the river mouth station is in accordance with each salinity profile. In the low flow season of May 2001, salt water reached as far upstream as the mound at 28km near flood tide, and possibly entered the pool at 33km. The echo-sounding salinity profiles and the surface salinity data reveal the presence of strongly vertically-mixed water in the entire area invaded by salt water, although partly stratified structures may be formed during slack tide. The present echo-sounding system has proven to be very effective in unraveling the time-space behavior of salt water intrusion in the Mekong River.

The Holocene Jomon transgression was recorded in sediments at the archeological site in the Shimane University，which were deposited in the most inner part of the lagoon．Marine mud deposition in back marsh condition indicates start of the transgression，which is marked by the Kikai-Akahoya tephra of 6300 yrs BP． Marine muds are characterized by fluctuating values of LOI（loss on ignition），total sulfur contents（TS），and Fe_2O_3 / Al_2O_3 ratios and these values are relatively higher than those of the non-marine ones in this section．Rb/K also shows fluctuation indicating Rb enrichment in under marine condition，probably related to Rb adsorption on clays．These sediments of this section show higher CIA（80～85）suggesting derivation of highly weathered material from the source or sorting of the clays．Ti/Zr shows gradual increase in the Jomon age，suggesting heavy mineral fractionation related to the transgression． High stand in sea-level probably lasted until middle Jomon age（4500 yrs BP），and consequently effects of fluvial inputs were dominated due to lowered sea-level．Gradual decrease in Al_2O_3 / TiO_2，SiO_2 / Al_2O_3 and Ti/Zr，and increase in Nb/Y and Zr/Y may be related to the source compositional changes due to the widening of the paddy field in the Yayoi age from 2400 yrs BP．

The Churia (Siwalik) Group of West Central Nepal, reported in previous papers (Tokuoka et al. , 1986, 1988)is traceable stratigraphically and structurally to the present study area. The group is divided into the Arung Khola, Binai Khola, Chitwan and Deorali Formations in ascending order, has a total thickness of 4,000 to 6,000 m and ranges in age from about 15 Ma to the Pleistocene . The group as a whole , is comprised of a coarsening-upward sequence , reflecting the rise of the Himalayas. The Churia group is separated from the Midland Group by the Main Boundary Thrust in the north and from the Alluvial deposits in the Gangetic Plain by the Frontal Churia Thrust in the south. The Central Churia Thrust divides the Siwalik (Churia) Hills into North and South Belts. A geologic map, columnar sections and route-maps are shown in detail in 10 appendix-figures. The results of paleocurrent analysis and sandstone petrography are also discussed in the present paper.

The continuous sequence of the Permian and the Lower Triassic Systems was fully examined paleontologically and sedimentologically in Abadeh region, Cenral Iran. Based on the correlation of the Permian in the Tethys province by means of fusulinid, ammonoid and conodont zonations together with brachiopod, coral and bryozoan fossils, it is concluded that the Upper Permian is reasonably classified into three stages, the Abadehian, the Dzhulfian, and the Dorashamian. Biostratigraphical and sedimentological study indicates a paraconformable relation between the Permian and Triassic, and the equivalent of the lower half of the Otoceras woodwardi zone is missing as judged from the conodont zones. The Dorashamian is older than the Griesbachian or Gangetian, and not the equivalent of the latter. The faunal change is related to not only local environmental change but universal causes. A remarkable attrition of species began in the Dzhulfian and reached a climax at the end of the Permian. Almost all the species had disappeared by the end of the Permian corresponding to the progressive shallowing and retreat of the sea. Rapid transgression and incoming of new organisms at the beginning of the Triassic is evident in the lithofacies and biofacies of the Lower Triassic.

The Permian and Triassic boundary was examined at Thini Khola area and precise columnar sections were obtained at three localities. The succession near the Permian and Triassic boundary is divisible into the calcareous sandstone part of the lower, orange dolomite part of the middle and thin-bedded limestones with mudstone seams of the upper, and the Permian and Triassic boundary is reasonably drawn between the middle and upper parts on the basis of already known occurrences of ammonites and newly found some conodonts. It was also discussed that extreme shallowing and regression of the sea at the end of the Permian occurred in most Tethyan realm and that transgression at the biginning of the Triassic was rather uniform and simultaneous.

The uplift and erosion of the Himalayas has resulted in a vast pile of terrestrial sediments called the Siwalik Group deposited at the frontal deep of the mountains. The Churia (Siwalik) Group of the Arung Khola area in the Churia Hills was studied in 1982, 1984 and 1985. The Group is bounded by the Main Boundary Thrust in the north and Frontal Churia Thurst in the south. It consists of a north and south belt separated by the Central Churia Thrust. The group is divided into the Arung Khola Formation (2,100 m in thickness), Binai Khola Formation (2,800 m), Chitwan Formation (700 m) and Deorali Formation (450 m) in ascending order. As a whole, the group comprises a coarsening-upward sequence, reflecting the rising Himalayas. The paleomagnetic polarity stratigraphy of the Churia Group has been successfully established.Detailed mapping and sampling made it possible to draw a paleomagnetic iso-polarity zone map. Magnetostratigraphically the Al and Am Members of the Arung Khola Formation are correlated to Chron 10-15, the Au Member of the Formation to around Chron 9, the Binai Khola Formation to Chron 8-Gilbert Reversed Polarity Chron, and the Chitwan and Deorali Formations to Matuyama Reversed Polarity Chron. Lithostratrgraphic nomenclature of "Lower, Middle and Upper Siwaliks" is different chronologically between the Siwalik Group of the type area in Pakistan and the Churia Group in Nepal. Sedimentation rate is calculated to be between 0.2 to 0.5 mm/yr in the Churia Group. Sedimentary studies have clarified the development of fluvial fan-river systems and their hinterlands. The Great Himalayas began their bigorous upheaval movements at about 10 Ma, which is reflected well in frequent intercalations of "Pepper-and-Salt Sandstones". Many freshwater molluscs have been discovered in the present area and were identified to the generic level. Most geologic structures of the present area are still active now, and are reflected well by geomorphologic features. Syn-sedimentary tectonic movement or syn-tectonic sedimentation characterises the Sub-Himalayan foothills, which may be interpreted by underthrusting of the Sub-Himalayan terrane against the Lesser Himalayan terrane .

In the present study area, the Churia Group is divided into the Arung Khola, Binal Khola, Chitwan and Deorali Formations in ascending order which attains a total thickness from 3,000 to 5,000 meters and ranges in age from about 16 Ma to Recent. In the adjoining area to the east, TOKUOKA et al. (1986) have established the standard stratigraphy of the Churia Group on the basis of paleomagnetic study. The stratigraphy and structures are very well traceable to the present study area. The lower member of the Arung Khola Formation is distributed to the north of Central Churia Thrust (C.C.T), whereas the strata from the middle member of the Arung Khola Formation to the top of the Deorali Formation occur to the south of the Thrust.The C.C.T. has an E-W trend and is very well exposed at two locations, where the steeply dipping Arung Khola Formation of the northern belt is thrust over the gently dipping Deorali Formation of the southern belt. At Parewa Pahar Khola, one meter wide zone of fault-clay has been developed along the thrust. Some basaltic fragments have been discovered from the fault-clay. These fragments are interpreted to have been sqeezed out from the deeper part along the thrust plane.

A Permian convergent margin rock suite is discussed on the basis of the results of precise mappmg at the junction area of the Maizuru and the Kozuki-Tatsuno Belts. Middle to Late Permian radiolarians have been discovered from both the Kozuki unit (argillite-meta volcanicsbeded chert) and the Maizuru Group (predominantly mudstones). The newly proposed Tonoshiki Formation is composed of sedimentary breccias interpreted as being derived mostly from the Yakuno Ophiolitic rocks. Lower Permian radiolarians have been discovered from mudstone intercalated in the Tonoshiki breccias. The fomation is regarded to have been deposited on the ophiolite. The Yakuno Ophiolitic rocks together with the Tonoshiki Formation may have constituted a volcanic arc system, separating the Maizuru and Kozuki basins in Middle Permian time. The Tonoshiki Formation can be compared with the Upper Permian Upukerora Formation of the Maitai Group from the South Island of New Zealand, which was derived predominantly from the underlying Dun Mountain Ophiolite.

The Shimanto Terrain facing to the Pacific Ocean was a geosynclinal area during the Mesozoic to lower Tertiary. The Muro group in the Kii Peninsula, Southwest Japan, occupies the southern part and upper horizon of the geosyncline. In the previous paper (TOKUOKA, 1967) the writer reported on the coarser clastic sediments of the Shimanto Terrain in the Kii Peninsula, and discussed its development. He concluded that the provenances of the Shimanto geosyncline were mainly in the northern geanticlinal regions, but that there must have been an old land to the south of the geosyncline, now foundered to ocean depths, from the discovery of exotic gravels. These exotic gravels are orthoquartzites, which have never been found in the present Japanese Islands. He collected and examined 391 samples of orthoquartzitic gravels from the indurated conglomerates in the Muro group at the southern extremity of the Kii Peninsula. In the present paper he will describe their occurrence, size, shape, roundness, rock color and internal sedimentary features. Eighty-six specimens observed under the microscope to clarify their textural and compositional properties will be described. Also considerations will be given to orthoquartzites themselves. Orthoquartzitic gravels in the Muro group have similar characteristics with typical cratonic sandstones such as Sinian quartzites in China or other Precambrian sedimentary quartzites which are distributed worldwide. It may be concluded that there had once been a source area, a part of which must be composed of Precambrian quartzites, to the south of the Shimanto geosyncline, and that it sank below the Pacific Ocean at the close of the geosynclinal development (probably at the end of the lower Miocene).

The Shimanto Supergroup in the Kii Peninsula is divided into two groups, i.e. the Hidakagawa Group in the northern part and the Muro Group in the southern part. The former is mainly Cretaceous and the latter is early Cenozoic. In this paper conglomerates and sandstones of the two groups are treated with, and several considerations on the geologic development of the Shimanto Terrain are given. In the Cretaceous the Shimanto Terrain was in a eugeosynclinal condition, while in the early Cenozoic it changed to be in a miogeosynclinal condition. The change of environment is shown in the differences of megascopic characters of clastic sediments and properties of sandstones. The provenances of the Shimanto Terrain can be generally sought to the north of the geosyncline, that is, the so-called Meso-Volcanics in the Inner Zone, various rocks in the Ryoke Metamorphic Belt, the Paleozoics in the Chichibu Terrain and the so-called Torinosu Group. After the close of the Shimanto geosyncline a marine transgression occurred again at the Middle Miocene, and formed the Kumano and Tanabe Groups. Their basins were smaller and more local in comparison with the Shimanto geosyncline. Clastic materials were supplied mainly from the Sambagawa Metamorphic Belt and the Muro Group. Orthoquartzite gravels were commonly found from the conglomerates in the southernmost district of the Muro Group. They are supermature orthoquartzites with excellent sorting and rounding. These rocks cannot be seen in the present Japanese Islands and furthermore the paleocurrent data of this district show apparently from south to north direction. Such being the case, it may be reasonably concluded that a missing land once existed to the south of the Shimanto geosyncline where nowadays is the Pacific Ocean.

A team of Japanese and Indian Geologists carried out detailed studies of the Permo-Triassic sections in the Srinagar region, Kashmir, during 1969. This report embodies certain conclusions arrived at in the light of these studies. The section at Guryul Ravine is described in detail, being the best in the Srinagar region. Lithological and faunistic comparisons with other areas examined are also referred to. The different faunistic zones of the Lower Trias of this area are compared with other important extra-Indian occurrences. The Zewan Series (Permian) at Guryul Ravine is succeeded by Lower Triassic beds. The arenaceous sediments pass into calcareous through argillaceous sediments. There is neither an intraformational nor interformational unconformity indicative of a hiatus in deposition. Many characteristic Permian elements survived in the lower part of the Lower Trias, constituting a zone of mixed fauna of Permo-Trias. This suggests a rapid faunal change from Permian to Lower Trias but not discontinuous. The lithology however supports a gradual change from Palaeozoic to Mesozoic. The advent of Lower Trias is marked by the appearance of characteristic species like Claraia stachei (BITTNER), SPATH in the dark shales. The paper also records a number of important Lower Triassic ammonoids (Otoceras, Glyptophiceras, etc.), which were so far not known from the Srinagar region. Considering the evolutionary position of some of the species of Otoceras, the boundary between the Permian and Trias is tentatively placed just below the advent of Claraia stachei.