68 BUREAU OF AMERICAN ETHNOLOGY [BuU. 179 



fied with the several foci, however, have been found on the surface 

 of other sites where they tend to substantiate, in a general sort of way, 

 the associations observed at the excavated sites. Some of the Fulton 

 Aspect foci are founded on two or more excavated sites although the 

 excavations in several cases were very limited, actually being more on 

 the order of "test" excavations than anything else. But the Texarkana 

 Focus is predicated primarily on the Hatchel Mound, the Frankston 

 Focus on the Saunders Site, and the Belcher Focus on the Belcher Site. 



Examination of the history of Caddoan Area archeology reveals 

 that the present classification of foci came about in tliis manner: 

 The few individuals or institutions who were particularly interested 

 in Caddoan area sites, and who were fortunate enough to be finan- 

 cially geared for extensive excavations, naturally began their investi- 

 gations with the largest, most promising sites that were readily 

 accessible. Few comparative data were available to these pioneers, 

 so there was little possibility of accurate analysis and interpretation. 

 The basic areal synthesis was accomplished by Krieger subsequent 

 to the W.P.A.-"millionaire archeologist" era, but the focal definitions 

 have been necessarily founded, for the most part, on those previous 

 excavations. Kegional specialists such as Clarence Webb have con- 

 tributed data acquired at a relatively late time, but limited resources 

 have tended to restrict their investigations to surface collections and 

 small-scale excavations. Data made available by the regional special- 

 ists were utilized fully in Krieger's areal synthesis, and, while they 

 fit the focus classifications in general, the focal definitions are never- 

 theless based fundamentally on the larger excavated sites — with one 

 site to a focus in many cases. 



The most sensitive and diagnostic markers for identifying a focus 

 are pottery types. In compiling the trait lists for the various foci 

 it was observed that frequently one particular type occurred in quan- 

 tity in not only one, but in two or even more focal contexts. These 

 types were thought of as being shared by the foci concerned. Some- 

 times, however, a small quantity of a type identified with Focus A 

 may be found in a component of Focus B. The tendency in these 

 cases has been to think of the type as trade material or an expression 

 of influence on Focus B by Focus A. 



At this point I should like to back off from the McKem system 

 and its application in the Caddoan Area and consider factors re- 

 garding the distribution of types in space and time. Axiomatic to 

 the discussion to follow is the concept that — barring some abrupt 

 physiographic or cultural barrier — the geographical distribution of 

 an archeological type tends to assume a lens-shaped pattern. That 

 is, there is normally a relatively heavy concentration in the central 

 portion of a distribution pattern and a thinning toward the periph- 

 ery. Sometimes barriers, such as an ocean, precipitous mountain 



