150 BUREAU OF AMERICAN ETHNOLOGY [Bull. 177 
origin. Nothing is known of the coast between the Mahaica and Abary 
Rivers so that the exact limit of the late Mabaruma Phase expan- 
sion cannot be specified at present. Survey of the Abary River 
produced sites of a different culture, designated as the Abary Phase 
(fig. 58), which shows clear indications of contact with late Mabaruma 
Phase sites, possibly those of the adjacent East Coast Demerara (see 
pp. 186-187 for details). 
A somewhat comparable expansion into the Orinoco delta has been 
postulated by Cruxent and Rouse (1959, pp. 237, 262) to account for 
the appearance of their Apostadero style, which closely resembles the 
late Mabaruma Phase pottery in decorative technique and motif (op. 
cit., pls. 102-104). Since Apostadero is separated from the earlier 
Los Barrancos style by an intrusive culture using sponge spicule 
tempered pottery and designated as the Guarguapo style, these 
authors do not recognize the Apostadero style as a continuation of the 
Barrancoid tradition. The situation in British Guiana, however, 
makes it quite clear that the Apostadero style is a variant of the late 
Mabaruma Phase. Cruxent and Rouse (op. cit. pp. 233, 287) date 
its appearance in Venezuela as post-European because of the presence 
of European trade sherds. In terms of the British Guiana sequence, 
this dating is within the realm of possibility. 
The last group to settle in the Northwest District was the Koriabo 
Phase, whose area of occupation centers on the Barima River (fig. 58). 
In paste, vessel shape, and decoration, the pottery of this Phase is 
distinct from that of the Mabaruma Phase, with the result that trade 
sherds are easily recognized. While all Koriabo Phase sites contain 
a considerable quantity of Mabaruma Phase trade sherds, Koriabo 
Phase trade sherds are limited to sites in the late part of the Maba- 
ruma Phase sequence, making it possible to estimate the time of arrival 
of the Koriabo Phase in the Northwest District of British Guiana as 
somewhere around A.D. 1200 by correlation with the estimated 
Mabaruma Phase time scale. 
In searching for the derivation of the Koriabo Phase, the distinc- 
tive nature of the ceramic complex is helpful. Vessel shapes include 
flaring rim bowls (e.g., Koriabo Scraped Form 1) and angular rimmed 
jars (e.g., Koriabo Scraped Forms 2 and 3). Bowls frequently have 
lip ornamentation in the form of lobes (pls. 34, 35). Incised and 
scraped decoration consists of simple patterns, sometimes embellished 
with low relief (pls. 38, 35, 36). Sherds with features very similar 
to these have been recovered from the Charlesburg site near Parama- 
ribo on the coast of Dutch Guiana by Peter Goethals (MS.), who 
kindly allowed us to examine his material and manuscript in detail. 
The same complex associated with the Koriabo Phase occurs here, 
including rim lobes, incised and scraped decoration accompanied by 
