Archaeological sites are often dated through seriation analysis of artifacts found on the site's surface. This relative dating method remains common despite the widespread availability of absolute dating methods because it is fast and cost-effective compared to scientific dating methods such as radiocarbon dating. Surface seriation is especially important for regional survey studies that involve a large number of sites and little to no excavation. In this context it is important to ask: are surface assemblages as reliable an indicator of the age of a site as determined through excavation? This unique study addresses this question using data from seven sites in the Virú Valley on the north coast of Peru. Surface assemblages are compared with excavated ones using the G-test statistic. It is found that surface assemblages do not closely resemble excavated ones in a statistically significant sense. Nevertheless, the relative date of surface assemblages typically resembles the relative date of excavated assemblages. Caution is urged when dating surface assemblages purely through seriation because the surface may not actually be representative of excavated assemblages.

Highlights:-The territorial-expansion model is examined in context of the development of the Virú state Evidence is presented to show that the Virú state incorporated the earlier Puerto Morin polities and that a three-tiered settlement hierarchy existed at this time. Drawing from cross-cultural evidence and recent studies on Virú expansionary dynamics, I propose a hypothesis that the Virú state expanded rapidly throughout the valley early in its developmental history and pursued a policy of territorial consolidation later in its history. Ultimately, the Virú case supports the territorial-expansion model of early state development.

The territorial-expansion model, recently proposed as a general model to explain the development of first-generation states, is tested in the Virú Valley of Peru. The Virú state developed around 200 BC and is the earliest known state on the north coast of Peru. The settlement patterns and settlement hierarchies of the Virú Period (ca. 200 BC – 600 AD) are compared with those of the earlier Puerto Morin Period (ca. 400 – 200 BC) to investigate processes of territorial expansion. Two independent polities and several outlying communities occupied the valley during the Puerto Morin Period whereas settlement during the Virú Period was extensive, populations surged, and large swaths of the valley were settled for the first time. Evidence is presented to show that the Virú state incorporated the earlier Puerto Morin polities and that a three-tiered settlement hierarchy existed at this time. Drawing from cross-cultural evidence and recent studies on Virú expansionary dynamics, I propose a hypothesis that the Virú state expanded rapidly throughout the valley early in its developmental history and pursued a policy of territorial consolidation later in its history. Ultimately, the Virú case supports the territorial-expansion model of early state development.