Tuff beds of Hverfjall eruption about 2400 years ago, showing volcanic pisolites formed like hailstones in ash falling during rain, and vertical hole where birch tree was buried in tephra. August 4, 1960.
Tunnel valley. 1. Moraine landscape. 2. Tunnel valley. a. Main valley. b. Lateral valley. c. Lake basins. d. Lagoon of liman type. e. Bay; the sea-transgressed part of the valley. 3. Post-glacial erosion valley. f. River valley eroded in the bottom of the tunnel valley. 4. Isthmus built in spit growth. g. Oldest southerly spit. h. Oldest northerly spit. 5. Barred foreland. Source: Atlas of Denmark.
Tunnel-meltwater glacial complex. 1. Moraine plateau. 2. Tunnel valley. a. Mosso basin. b. Saltena valley. 3. Fluvio-glacial valley. 4. Valley terraces, resistant parts of earlier valley bottoms, consisting of metlwater deposits. 5. Dead-ice depressions. c. Salten Langso. d. Bog depression. e. Kettle-holes. 6. Post-glacial erosion valleys, dissecting the moraine plateau. 7. Recent valley bottom. f. Gudena. g. Delta of the River Gudena in the Mosso basin. Source: Atlas of Denmark.
Turbidity currents. Topographical profile along the path of the 1929 Grand Banks, turbidity current showing cable breaks, cores and velocities of the current. Jacobs et al., 1959, p. 241.
Two samples of quick clay showing startling contrast. Column of undisturbed clay (left) holds 11 kilograms (24 pounds). It can support 2,100 pounds per square foot surface. Another piece of the same clay pours like a liquid afer being stirred in a beaker. No water was added. Demonstration was made by Carl B. Crawford of the National Research Council of Canada (Kerr, P.F., 1963, Sci. Amer. Nov., p. 134).
Two types of slide shown schematically. At top three blocks of earth have rotated in clay-water slurry. In the other slide total liquefaction has occurred and water forced out of the clay has formed a pond. The vertical dimension is exaggerated five times. Typical slide has a figure-eight appearance. Material the leaves a hollow at the head region piles up at the foot. The low cliff at the neck is often the bank of a river (Kerr, P.F., 1963, Sci. Amer. Nov., p. 138).
Type section of Exshaw shales on Jura Creek near Exshaw, Alberta. Overlying the black shales is the Banff to the left, underlying the shales to the right is the Palliser. May, 1961.
