This is worth checking out (caution: PDF file link)
: "On Pure Land Buddhism and Ch'an/Pure Land Syncretism in Medieval China," T'oung Pao 88, no. 4-5 (June, 2003), pp. 282-331.
Thanks to some1 for pointing out the online links for Prof Sharf's articles.
As the article shows, in China at least, the distinction, if any at all, between Pureland and Chan, is not as great as many would make it out to be. And so-called "syncretism" is perhaps less of a later (eg. Song dynasty) development, as it is the original situation of Mahayana practice in China as a whole.