Whо wrоte, “I present yоu with а key; I hаve not heаrd of the like, yet framed, since it pleased God to bring that mighty continent of America to light. Others of my countrymen have often, and excellently, and lately written of the country (and none that I know beyond the goodness and worth of it). This key, respects the native language of it, and happily may unlock some rarities concerning the natives themselves, not yet discovered.” In what book was it written? And what is the signifance of the quote in the specific context of the author's work? Answer in ten sentences.