puaneand ARCHEOLOGY IN BRITISH GUIANA 147 
Phase, which soon dominated the Aruka River area, displacing or ab- 
sorbing the already semiacculturated, earlier inhabitants (fig. 58). 
The origin of the Mabaruma Phase can be determined with unusual 
precision, thanks to the work of Cruxent and Rouse at the mouth of the 
Orinoco River. The sequence of pottery-making cultures in that area 
begins with Saladero and continues through Barrancas, Los Barran- 
cos, Guarguapo, and Apostadero styles (Cruxent and Rouse, 1959, pp. 
211-237). The characteristic features of the early Mabaruma Phase 
equate most closely with those of Los Barrancos, where incision pre- 
dominates over modeled-incised decoration (rather than the reverse 
which was typical of the earlier Barrancas style). The fact that Los 
Barrancos style is one of the most widespread at the mouth of the 
Orinoco suggests that this time was one of expansion of the culture, 
of which the movement into British Guiana is an expression. The 
carbon 14 date for Los Barrancos style at the mouth of the Orinoco is 
1,370+90 years ago or ca. A.D. 575 (op. cit., p. 230), which seems 
reasonable in terms of the British Guiana sequence and is acceptable as 
an approximate beginning date for the Mabaruma Phase in British 
Guiana (fig. 126). 
There is quite a bit of change in Mabaruma Phase pottery during 
the estimated thousand years or so that the Phase appears to have en- 
dured in British Guiana. This change tends to be gradual, although 
there are several points at which a number of new vessel shapes and 
decorative motifs appear almost simultaneously, suggesting that an 
outside influence may be involved. This clustering was the basis for 
subdividing the Mabaruma Phase sequence into early, middle, and late 
segments (fig. 49). The existence of an initial date of around A.D. 
500 (by correlation with the lower Orinoco date for Los Barrancos) 
and a terminal date of about A.D. 1600, when European settlement 
began in the area, makes it possible to establish a tentative estimated 
time scale. Assuming that the changes of pottery frequencies are 
generally equal throughout, the sequence can be arbitrarily divided 
into 100-year intervals. This subdivision gives guess dates of A.D. 
500-850 for the early period, A.D. 850-1250 for the middle period, 
and A.D. 1250-1600 for the late period. 
The early period is characterized by such typical Barrancoid traits 
as modeled-incised adornos, broadline incision on a broad flange 
rim, annular bases, and sand temper. The middle period is marked by 
the introduction of a number of simple rounded bowl and jar forms 
and several new decorative motifs, including a cruder form of adorno 
and new combinations of punctate and incision. The large number 
of innovations that appear almost simultaneously at this time sug- 
gest some kind of outside influence, but the origin of this is difficult 
to trace. The only really unique element to appear is the small, 
