As discussed in Pottery Basics, the use of fired clay as a tempering agent is common in South Carolina. Both ground up sherds and what appears to be purposely fired clay were used. It is not always easy to identify bits that clearly came from sherds however, so the more inclusive term "grog" is used in general. As discussed below, this is a bit problematic.
Hanover and Wilmington are probably the same "ware" but there may be three or more wares hiding behind this bland paste and surface treatment. Generally Hanover is the name used for sherd/grog tempered wares north of Charleston, and Wilmington to the south. St. Catherines is usually thought of as a Mississippian ware, but the dates that have accumulated over the years suggest that the coarser tempered Hanover and Wilmington wares were being made at the same time.
Joe Herbert and John Cable have posited two phases of Hanover in the Cape Fear and Santee drainages in North and South Carolina that appear to be valid on the Pee Dee at 38DA75 as well. Hanover I is given a date range of 400-800AD. Hanover II dates from 800-1500AD, though the latest dates may be specious.
The earlier phase, which Cable also calls the Berkeley series (2002) has a sandy paste, with finely crushed grog. It is more often cord marked, and decorations include fabric impressed and check stamped. Hanover II has a fine, silty paste -Anderson's "fs/clay" paste- with little sand and more coarse grog. It is most often fabric impressed. In more recent and detailed analysis John Cable identified seven paste variants which should have temporal significance, but unfortunately empirical dates could not be obtained (Cable et al 2005: 120). Sean Taylor has identified seven distinct paste groups for clay tempered pottery at the Kolb site as well.
Hanover appears to be focused on the coast at about the NC-SC line, but is found well inland in the Cape Fear, Pee Dee, and Santee drainages. Grog tempered wares are less common inland on the and Savannah, but are found on the coast as Wilmington and St. Catherines wares. The St. Catherines variant tends to be more compact, finer ground bits of grog, and finer cord, but the distinction should be made with proper consideration to context, rather than on a sherd by sherd basis.
The first dates obtained in South Carolina for either ware came from South and Widmer's work at Fort Johnson. There oyster shell was dated to 2100+/-60BP and 2130+/-100BP (150, 180BC). Calibrated with the marine reservoir effect in mind this date changes considerably to a median of 270AD for the first, and 237AD for the second. The full extent of the reservoir effect's skewing of dates from oysters, which are found in brackish water rather than seawater, is not known (see Thomas et al 2008), but these dates are more in line with the collection as a whole, though still on the low end. Dates associated with Hanover and Wilmington collected for this project, all calibrated with Calib 5.1 and the marine effect applied where appropriate, range from 55-1586AD, with the majority falling in a more or less continuous arc from 491-1356AD.
Making generalizations about surface treatments that may be temporally diagnostic is difficult. Grog tempered wares that are virtually the same are found from North Carolina to Florida and they were made for at least a thousand years. Thus local variants (crushed sherd + heavy cord, for instance) that are temporally significant may may be seen in different places at different times, so that the variable a researcher at the mouth of the Savannah sees as early may occur on the Cape Fear later.
Joe Herbert (2009) points out that this wide time range may reflect our tendency to lump all grog tempered wares together, and suggests that a more detailed, comparative analysis will be necessary to identify meaningful variation. He and Jon Cable have both pointed to variants with large temper and a sandy paste, and with a finer, silty paste. These are called Hanover I and II by Cable (et al 1998) but empirical dates cannot be assigned.
On the Georgia coast Chester DePratter (1991) uses temper size to sort Wilmington from St. Catherine's ware but does not recognize Hanover. Wilmington has 3-6mm pieces. St. Catherines is generally described as having a fine grog temper. The dates from Wilmington at St. Catherines Island range between 480 and 690AD (Thomas et al 2008). Dates for St. Catherines range from about 750-1250AD. However, four Hanover dates from 38DA75 range between 827 and 1132AD (Calib 5.1 applied). These are clearly tempered with large, lumpy inclusions sometimes clearly identifiable as sherd fragments, not finely ground grog.
So, there is variation in the grog tempered wares that is probably temporally sensitive, but there is also a spatial element. As Joe Herbert said, detailed comparative analysis and systematic dating is needed.
The literature on these types is introduced below, and links are provided to sources, descriptions and images. The Hanover type was defined by Stanley South (1976). It is discussed in detail by Joe Herbert (2003 , 2009, and elsewhere). John Cable has systematically analyzed Hanover assemblages in detail, and provides hard data for comparison (Cable 1998, 2002). Wilmington was named by Joseph Caldwell and Antonio Waring (1939) for a site on Wilmington Island, near Savannah. It is discussed in detail by DePratter (1979, 1991).