Ichaboe, a small island off the coast of Nambia, once towered high with mounds of seabird guano - an excellent fertilizer.  Large scale exporting of the “white gold” began in 1843 and for a few years 450 ships were streaming to and from the island, shrinking the size of the island by 25 feet. 

One of those ships was the Shakspeare, which docked in Atlantic Basin in May 1845. 

While the frenzy is long over, the guano from the island, considered some of the best, is still sold for fertilizer.

Text of article from the Morning Courier and New-York Enquirer. May 27, 1845: 

GUANO – The cargo ship Shakspeare, from Ichaboe, of very superior quality, landing at the Atlantic Dock, Brooklyn.  It has been well ascertained, that this Guano is superior to any other, as it brings forward crops earlier, and is equally lasting.  For general farming, it will increase crops from 30 to 50 percent and for market purposes it will enhance its value at least 200, and in some instances 400 percent.  300 lbs. is sufficient for an acre.