results of studies of siliceous rock availability in two areas of the southern end of the deseado massif (la gruta and viuda quenzana) are presented. variability is compared in scales ranging from ca. 1 to 25 km. the results point to the existence of variability at both scales. the recorded performance is high in both spaces, but siliceous raw materials of excellent and very good quality are more frequent in viuda quenzana, where chalcedony and other siliceus rocks are the most frequent ones. this variability in siliceous rock availability coupled with the frequency of rock shelters and caves (more abundant in viuda quenzana than in la gruta), and the presence of temporary water bodies which have probably varied in relation to rainfall over time must have been important for hunter-gatherers strategies.