The Complete Work of Charles Darwin Online

RECORD: Darwin, C. R. 1856.09.14. I shd think in a high cliff 1 inch in 100 years was ample allowance for whole line to be degraded. CUL-DAR205.9.316. Edited by John van Wyhe (Darwin Online, http://darwin-online.org.uk/)

REVISION HISTORY: Transcribed by Christine Chua and edited by John van Wyhe 10.2021. RN1

NOTE: See record in the Darwin Online manuscript catalogue, enter its Identifier here. Reproduced with permission of the Syndics of Cambridge University Library and William Huxley Darwin. The volume CUL-DAR205.9 contains notes on palaeontology and geology [regarding theory of evolution].

[316]

I shd think in a high cliff 1 inch in 100 years was ample allowance for whole line to be degraded. Now in geograph. miles there are & say 40 miles from N. to S. Downs

2000 yards [x] 40 [=] 80,000 yards [x] 36 miles in a yard [=] 480000 [+] 2400000 [=]

2,880,000 {inches between N. & S. Downs [x] 100, years for one inch [=] 288,000,000

288 million years!

This excludes all the time dry land after the fall of cliff remnant of whole without total thickness of chalk 800 ft & all the underlying strata

The distance is not above 20 miles! Look to Ramsays paper 1 inch in a thousand years not too quick, if we say 1 from cliff & 1000 feet high.

[in margin:] Sept. 14 /56/

Citation: John van Wyhe, ed. 2002-. The Complete Work of Charles Darwin Online. (http://darwin-online.org.uk/)