If I may weigh in on this -- we don't need to dump on 20th-century
archaeological sites -- ARPA applies to them, now, too. We all have
different research interests, and early- to mid-20th-century archaeological
sites do have value. As I have written and spoken about (see 1995 CRM
article at http://crm.cr.nps.gov/issue.cfm?volume=18&number=06/Sup),
archaeology has a lot it can contribute to our understanding of this
important period in our history precisely because it looks at the past
through a different lens than does historical research
Sue Henry Renaud, RPA
(my opinions, not those of my agency)