Though correspondence has never ebbed so low, CD is constantly in his thoughts.

Observations on cheetahs used as domesticated hunting animals.

Finds geographical barriers sometimes separate species, but also finds species that remain separate where there are no barriers to migration.

Colour "individuates" isolated animal species.

Plains and alpine animal distribution show altitude not strictly analogous to latitude.

Impact of timber cutting on climate has led to extinction of crocodiles.

Will discuss coal formation in letter to Edward Forbes.

CD often asked whether isolated mountains in southern latitudes had closely allied representatives of Arctic and north temperate plants; JDH has found a representative barberry.

Making for Darjeeling via Calcutta.

Brian Hodgson reading CD’s Journal of researches with delight.

Forwarding breeding pamphlets.

JDH recommends P. S. Pallas on degeneration.

CD’s facts on sex in barnacles startling.

Hugh Falconer’s health.

Hugh Falconer’s misbehaviour.

Waiting out rains at Brian Hodgson’s.

Will make botanical transverse section of Himalayas from plains to snow.

Arrangements to pass Sikkim Rajah’s territory.

No evidence of glacial or diluvial action in sub-Himalayan mountains. No evidence of detrital coal formation.

Hodgson’s replies to CD on introduced species and hybrids.

Physical description of Sikkim mountains.

Travelling through Kinchin snows.

Transported boulders.

Continues prior letter of this date. Has received CD’s [1202]. Thanks CD for saving his correspondence.

Sent "a yarn about species" in October mail.

Some "puerile" JDH letters printed in Athenæum.

Requests CD extract anything valuable from his letters to CD and Lyell for Athenæum.

CD’s complemental males in barnacles wonderful.

Warns CD to drop his battle about perpetuity of names in species descriptions.

Pleasure at receiving CD’s scientific letters to JDH and Hodgson.

The H. Wedgwoods’ pecuniary loss.

Condolences at CD’s father’s death.

Rajah harasses JDH’s work. Lack of supplies, rain, malarial valleys, and landslips make going difficult. Cannot get into Tibet.

"Twenty species [of plants] here [Camp Sikkim] to one there [Tierra del Fuego?] always are asking me the vexed question, ""where do we come from?""."

From observation of terraces descending to steppes and plains of India, he thinks that the Himalayas were once a grand fiord coast.

Has information CD requested on Yangsma valley. JDH’s detailed hypothesis of origin of dam there. Does not agree with CD’s interpretation.

CD partly right. JDH was calling "stratification" what CD calls "foliation". Answers CD’s question on cleavage foliation in Himalayas. Glacial action.

Charmed by CD’s Admiralty instructions on geology [in Manual of scientific enquiry (1849), Collected papers 1: 227–50], but complains he does not give prices of books and instruments he recommends.