This system had many advantages. Records were readily kept up to date, problems that suggested themselves as excavation progressed could be more closely defined and investigated, and artifacts could be expeditiously and finally cleared from the work area. The data sheets served as a field catalogue and covered the groundwork of the final statistical compilation. The number assigned each specimen referred not only to its catalogue entry but also its provenience. In 1947 we could not anticipate what might be found, nor could we establish immediately the significance of what we did encounter. Thus it has been our policy to save all worked stone and ship it back to the Museum of Anthropology at Berkeley for study. During the second season, however, we felt a little more discrimination was warranted in order to save the museum valuable storage space. Therefore, the bulk of the hammerstones and a number of complete, and all fragmentary, manos, metates, and scrapers were tabulated and piled into pit 21R4 before backfilling. [Illustration: Map 2. Tank Site LAn-1] FEATURES Since the Tank Site showed promise of being an unusual and important deposit, considerable care was observed during both seasons of excavation to isolate and expose any concentration of lithic remains which appeared to be in any way atypical of the average mound matrix. As a result, numerous associations of stones, such as mano caches, highly weathered inverted metates, and massive piles of rejected cores, broken manos and metates, and plain cobbles, were set apart from the rest of the site and given the term "feature." In some instances these features possess obvious meaning, as was true of the mano caches and the inverted metates, but in other instances the purpose remains unknown. If nothing else, this technique of isolating features as excavation progressed provided an adequate view of the internal structure of a village, a type of information largely lacking in southern California archaeology. The features described below represent a continuation of the series reported for 1947. _Feature 14 (pl. 19, b)._--Cache of 4 manos. The placement of these specimens precludes a chance affinity; they were closely grouped and each was standing more or less on end. No other artifacts were found in association. _Feature 15 (pl. 19, d)._--Owing to its areal extent, feature 15 is somewhat difficult to define. The complex of stone by which it is characterized has been arbitrarily broken down for descriptive convenience. There is no way of knowing whether the entire complex exemplifies a single unit or if in the course of time it merely developed from a single point of departure.