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the alluvium would form a succession of flights of steps; if one lake then we must suppose barrier in the very part, where barrier least probable. — The sea harmonizes well with character of mouth of valleys on Pampas.

If blocks above their parent rocks would be prove of subsidence — removal downwards by successive torrent spread out by sea — beach action — no one will dispute sea once came to Mendoza —

Will they introduce other causes to explain alluvium in valleys

 

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with slow course small erosive power therefore tendency of running water to deepen not to widen valley. Why is serpentine course result of little inclination?? — — It is simply as the inclination is little the force required to move it stream aside is not great. — Is there more degradation at first angle owing to momentum which the water has obtained. —

If inclination be great where arrow stands the force immediately deflected from (B) which would not have been case if inclination small. — [sketch]

 

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Lowe in his paper says land shells found with calcareous matter & concretions on coast of Madeira? How came it if this powder results from decomposed sea shells that land shells should be preserved in it — some error? (because more recent) Coquimbo on other hand? —

The widening a valley depends on serpentine course. — the latter (it is generally said) is consequence of rapid slow course, &

 

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The power of widening channel depends on power of deflection with stream retaining its force, now it will be evident that deflected stream cannot retain its force if inclination be great. There could not be great deflection in a "rapid". — is a familiar illustration. — Therefore stream has no tendency to widen course until inclination is become comparatively small, & when that is case force is lessened therefore rivers very ineffectual in widening valley — it is essentially a deepening agent

 

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[sketch]

Therefore when we have valleys of this structure as the inclination in all probability would be greater when flowing over (B) than when at (C) its tendency would be to cut a narrower channel instead of wider. — This applies to all vallies (except mere talus over cliffs edge of which limit cannot be great over) with very gently sloping sides

This argument is partly taken from De la Beche Theoretical Researches

 

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Athenaeum 1838 p. 137. Three inosculating rivers in Southern America ؟effect of subsidence —

Is same Institute. 1838 p. 40 or Phil Mag. Dec 1837 p. 520 Mr Fox on increase of temperature at great depths.

All Earthquake unaccompanied by Volcanos must be sought after proofs of sinking. — No Sweden!! swelling of rock from Heat.