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Summary A portable rainfall simulator was used to measure the runoff rates and soil losses from a freshly ploughed luvisol at Katumani, and a nitosol at Kabete, on a 6° slope at varying rainfall intensities. The soil losses from storms of 50 and 100 mm/h intensities, in which a total of SO mm rain was applied to plots in the wet moisture state, varied from 0.8 to 1.4 metric tons/ha at Kabete and 8.5 to 13.9 metric tons/ha at Katumani. The percentage runoff from these storms was 15 to 17 per cent at Kabete and 67 to 71 per cent at Katumani. The much greater runoff rates from the Katumani soils were shown to be due to surface capping caused by degradation of the surface structure. It has been proposed that soil credibility K factors of 0.4 and 0.04 could be used for the Katumani and Kabete soils respectively in the Universal Soil Loss Equation

Site Description B. COLTHARP The areas selected for study are located approximately 5 miles to the west and south of the town of Cisco, Grand County, Utah. This area, Highlight: The effects of contour furrows and gully plugs on known as Cisco Basin, is bounded on the north by the Book Cliffs and erosion and sedimentation within the Cisco Basin, Utah, were on the south by the Colorado River. It is typical of the upper Colorado evaluated over a 3-to byear period. Soils on the study area were River Drainage basin of western Colorado and much of Carbon, generally less than 10 cm deep and were developed from Mancos Emery, Garfield, Grand, Kane, San Juan, Uintah, and Wayne shale and sandstone. Contour furrows and gully plugs together aunties in eastem Utah. Mean elevation above sea level is 1,280 to held all runoff and sediment, while contour furrows alone held only a portion of the runoff and sediment. Diffkulties in constructing furrows on the contour resulted in a shortened useful life of the structures. Projected life expectancy of the contour furrows ranged from 6 to 12 years; for the gully plugs the projected life expectancy was from 14 to 33 years.

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The Antigonish Basin is one of several Carboniferous structural basins in northeastern Nova Scotia, the evolution of which have been cited as evidence for major detachment faulting within the Vis. Windsor Group of Maritime Canada. Evidence of extension in the Antigonish Basin takes the form of a major subhorizontal structure that closely follows the basin margins and has been interpreted as part of the regional Ainslie Detachment. Placed at the top of the basal Macumber Formation and reportedly characterized by several metres of calc-mylonite, the detachment is considered to have accommodated 10—25 km of westward transport of the evaporitic Windsor and overlying Mabou groups during the late Namurian-early Westphalian. However, deformation within the Macumber Formation limestone immediately beneath the detachment surface suggests local extension of Vis. age. Recumbent intraformational folds are overlain by depositional breccias that contain previously folded fragments and are themselves recumbently folded. These relationships suggest repeated movement that began soon after limestone deposition. Furthermore, fold asymmetry and the orientation of calcite veins and small-scale normal faults suggest variable directions of extension that converge on the centre of the basin located in St. Georges Bay. While these data do not preclude the existence of the Ainslie Detachment, they suggest that the Macumber Formation in the Antigonish Basin records an earlier episode of deformation that occurred in response to local gravity sliding rather than to movement on a regional detachment surface. RESUMÉ Le bassin d’ Antigonish constitue l’ un d’ une série de bassins structuraux du Carbonifère dans le nord-ouest de la Nouvelle-Écosse don’ t l’ évolution a été citée comme preuve d’ une dislocation importante par détachement à l’ intérieur du groupe viséen de Windsor dans les provinces Maritimes. On relève une preuve du prolongement dans le bassin d’ Antigonish sous la forme d’ une structure subhorizontale importante qui suit de près les limites du bassin et qui a été interprétée comme une partie du détachement régional d’ Ainslie. On estime que le détachement, situé au sommet de la Formation basale de Macumber et caractérisé, d’ après ce qu’ on dit, par plusieurs mètres de mylonite calcique, a permis le transport vers l’ ouest sur dix à 25 kilomètres des groupes sus-jacent de Mabou et évaporitique de Windsor au cours de la période du Namurien tardif-Westphalien précoce. La déformation à l’ intérieur du calcaire de la Formation de Macumber immédiatement au-dessous de la surface du détachement, laisse toutefois supposer un prolongement local à l’ époque du Viséen. Les plis intraformationnels couchés sont recouverts de brèches de sedimentation renfermant des fragments antérieurement pliés qui sont eux-mêmes repliés sur un plan axial horizontal. Ces rapports permettent de supposer un mouvement répété qui a débuté peu après la sédimentation du calcaire. De plus, l’ asymétrie des plis et l’ orientation des filons de calcite et des failles normales de petite échelle laissent supposer des orientations de prolongation variables qui convergent vers le centre du bassin situé dans la baie de St. Georges. Même si ces données n’ écartent pas la possibilité de l’ existence du détachement d’ Ainslie, elles permettent de supposer que la Formation de Macumber dans le bassin d’ Antigonish évoque un épisode plus hâtif de déformation, survenu à la suite d’ un glissement gravitationnel local plutôt que d’ un déplacement à la surface d’ un détachement régional.