The Florida Anthropologist Florida Museum of Natural History, University of Florida, Gainesville, FL 32611 Vol. 68 (3-4) September-December 2015 Charly Lollis, Neill J. Wallis, and Ann S. Cordell WAS ST. JOHNS POTTERY MADE WITH SWAMP MUCK AS TEMPER? AN EXPERIMENTAL ASSESSMENT St. Johns pottery is a distinctive Florida ware that occurs in abundance throughout peninsular Florida but rarely outside the state. The St. Johns series is deined by a fabric that contains abundant sponge spicules and a characteristic “chalky” feel when handled (Borremans and Shaak 1986; Goggin 1952:99; Holmes 1894:111-112). The origins of these qualities have been a topic of debate in Florida archaeology for many years (Borremans and Shaak 1986; Cordell and Koski 2003; Crusoe 1971; Espenshade 1983; Rolland and Bond 2003). Two opposing hypotheses have been proposed to explain the presence of spicules: “naturally-present” and “added-temper.” Some argue that St. Johns pottery was produced with clays that had spicules naturally occurring within them (e.g., Borremans and Shaak 1986; Cordell and Koski 2003), while others claim that spicules were intentionally added as temper to enhance the working properties of the clay (e.g., Rolland and Bond 2003). Systematic attempts to collect clays with abundant sponge spicules have proven mostly unsuccessful, but have been mostly limited to Duval and Brevard Counties (Espenshade 1983; Rolland and Bond 2003). To our knowledge, no replication experiments have successfully recreated a paste (a.k.a. fabric) that has the soft “chalky” feel and abundant sponge spicules of St. Johns pottery. The goal of this research is to better understand, through laboratory experiments, the process by which St. Johns series pottery was manufactured. Speciically, experiments were designed to test the possibility that added tempers imparted both the abundant sponge spicules and the chalky surface texture of the pottery. The soft chalky texture of St. Johns pottery is often attributed to the presence of freshwater sponge spicules in the clay (Borremans and Shaak 1986; Milanich 1994:246), but we argue that this relationship is one of correlation, not causation. A “chalky” feel in materials is imparted by the easy removal of extremely ine particles from the surface. For example, chalky substances such as chalk, talc, and gypsum can leave characteristic powdery residues on harder surfaces (such as chalkboards). The chalky texture of St. Johns pottery undoubtedly is also caused by particles exfoliating from sherd surfaces. Yet while spicules are among the particles sloughing off and removed when touched, their inherent shape imparts tactile qualities quite unlike the powdery residues of chalk, talc or gypsum. Spicules are silicate elements manufactured by freshwater sponges in their mesoderm and have needle- like structures that irritate the skin, much like iberglass (Borremans and Shaak 1986; Cordell and Koski 2003:114). The needle-like structures of spicules are a well-known skin irritant for people working in mucky soils, a fact that is corroborated by our own personal experiences (Davis 1912). Therefore, spicules seem a very unlikely source for the chalky texture of St. Johns pottery. We hypothesize that organic muck from shallow freshwater environments (e.g., bogs, ponds, and wetlands) is a likely candidate for tempering St. Johns pots. Muck consists of decayed, ine-grained organic matter that turns to a ine powdery ash when ired. This ash might have imparted the “chalky” (or “ashy”) feel of the pottery while also contributing sponge spicules, which are often abundant in muck deposits (Conley and Schelske 1993; Davis 1912). The replication experiment was conducted at the Florida Museum of Natural History Ceramic Technology Laboratory (FLMNH-CTL). Sediment samples from Florida archaeological sites were selected as the test materials. These included clays that are similar to St. Johns pottery in having a ine texture and low iron content, and muck and peat samples that are rich in sponge spicules. Raw clay samples and muck/peat samples were processed and combined in several different proportions to make clay test bars using molds in the lab. The bars were then broken into testing briquettes and ired to a series of increasing temperatures in the kiln. The experimental briquettes were compared to key characteristics of St. Johns pottery to determine if the experiment yielded successful replicas of St. Johns paste. These attributes include Mohs scratch hardness, surface and core coloring, oxidation, spicule abundance, grain size, and the subjective assessment of “chalky” texture. Background St. Johns series pottery—deined by abundant spicules and chalky texture—is found throughout peninsular Florida but is most abundant in Northeast Florida, particularly along the St. Johns River, from which its name derives. The heartland of the St. Johns culture, and its accompanying St. Johns pottery, is along the St. Johns River from Orange and Brevard Counties in the south to Nassau County in the north (Goggin 1952:15- 17; but see Ashley (2008) regarding the timing of St. Johns pottery in northern areas). The earliest chalky wares date to circa 1500 BC (Bullen 1971) and other vessels containing the characteristic sponge spicules occur even earlier in the Late Archaic Orange series (Cordell 2004). Classic St. Johns series vessels with abundant spicules were produced well into the historic era (e.g. Deagan 2009). A variety of types with this characteristic paste are deined by different surface treatments: St. Johns Plain (Goggin 1952:101-102), St. Johns Incised, Dunns Creek Red (both Goggin 1951:102), St. Johns Red on Buff (Goggin 1052:102-103), St. Johns Punctated, Oklawaha Plain, Oklawaha Incised (all Goggin 1952:103), St. Johns