“It is not clear that Polk knew what he meant by it. Expansionism, North or South, included California, but this meant little more than a recognition of Monterey, where the trade in hides centered, and a lively realization of the geographical importance of San Francisco Bay. . . .
“Of all the vast space east of the Sierra it was impossible to know anything except for the records of the fur trade and the few trails scratched across the deserts – and it does not appear that anyone now in official life except Benton knew any useful part of this. Even the great valleys between the Sierra and the sea, even the genial, pastoral, hospitable life of the Californians were little known. As late as ’46 no detailed, dependable map of California existed. There were few trustworthy descriptions, in English, of any part east of the coastal towns. Newspapers published letters from shipmasters or their passengers who touched the coast – romantic, flamboyant, packed with fable and misunderstanding. The War Department had a handful of reports, fragmentary, in great part inaccurate, ignored by everyone but Benton: it is not certain that Polk had ever heard of them. There were half a dozen books: the President had not read them. Lately the State Department had made a shrewd and intelligent merchant, Thomas O. Larkin, consul at Monterey. His reports were the one dependable source of information.”