Here’s a good blog post about its discovery and some of the implications involved:
“Sensationalising archaeological finds in pursuit of funding, access or political favour, however tempting, is a risky strategy – as we have noted previously in the case of Amphipolis. The importance of this particular find is indisputable, but it is not because of the shaky Kylon connection.
The Phaleron Delta cemetery may be one of the largest ever excavated in Greece. It was in use for almost three hundred years during a poorly understood period on the cusp between prehistory and the historical era. The large sample size will make it possible to reach significant conclusions about the population of Archaic Athens, its genetic makeup, its diet and its historical evolution. Moreover, the preservation conditions are exceptional, because the site lay in swampy ground in a river delta. In addition to the mass graves, it includes an amazing variety of funerary practices, including infant jar burials, funeral pyres, boat burials (with carved wooden boats fully preserved), and animal burials (including several horses) (further information and photos here). Archaeological techniques for recovery, conservation and analysis have progressed significantly since the first excavations on the site, but the sheer volume of material will undoubtedly pose a logistical, as well as a funding challenge for those involved (an international team based in the American School of Classical Studies in Athens has already been given permission to study the osteological material).”
(mass burial with evidence of violent death)