Asks whether the blind cave animals described by B. Silliman Jr [Am. J. Sci. 2d ser. 11 (1851): 332–9] belong to genera found only on the American continent.

On geographical distribution of Crustacea, CD asks whether northern genera sent species to the Southern Hemisphere or did southern genera send species north?

Does he know of any author who has described fossil trees in South Shetland Islands?

Asks whether Allegheny Mountains are sufficiently continuous so that plants could travel from north to south along them.

Hopes AG’s work on geographical distribution is progressing, as he has questions on plants common to Europe which do not range up to Arctic.

Are intermediate varieties less numerous in individuals than the varieties they connect?

Thanks for the magnetic theory [see GS's 1856-7-9] and agrees it argues against JH's ideas about Mahomet's coffin. Describes some interesting magnetic experiments JH has seen.