1997 Inner Harbor Excavation Season Summary

Eduard G. Reinhardt

Stratigraphic excavation in the inner harbor (Areas SW 2, 3, 4and TN 2; Fig. 1) was initiated to document ship wrecks which were partially uncovered in the 1996 season. Unfortunately, no extensive ship remains were found and only isolated ship timbers were uncovered.  However in the search for these shipwrecks, detailed stratigraphic information was uncovered from the inner harbor deposits that has greatly enhanced the archaeological interpretation of the evolution of the harbor.  The stratigraphic sections document the environmental evolution of the harbor from its building to its final destruction and answer many questions regarding the integrity of the harbor breakwaters (Fig.2).   No other excavation area in the harbor so clearly defines this history as in the sections from Area TN and SW.  These sections are so explanatory that we would venture to define this stratigraphy as a type section for the evolution of the harbor.

The recognition of these environmental changes over the course of the harbors history have been initially documented through paleontological, sedimentological and material cultural evidence.  Careful stratigraphic excavation of the deposits using metal caissons (Figs. 3, 4) and an underwater metal grid (Fig. 5) allowed the recovery of material culture in its sedimentary context.  Careful control of the material cultural evidence during excavation allowed a coherent corpus of material to be recovered from the four sections and the dates obtained from the four loci have very tight age ranges (Fig. 6).

Locus 004 (Fig. 2) was characteristic of deposition in a high energy littoral environment and the locus had well rounded cobble clasts, well rounded pottery which were both heavily bored and encrusted (Fig. 7).  The bioencrustation was particularly evident at the top of the locus where there was a thick and continuous unit.   Such encrustation would have required a high energy environment without sediment coverage. Pottery dates indicate that this environment probably occurred sometime in the 1st to 2nd c. AD (Fig. 6).  This date also indicates that the inner harbor was a high energy state by this time and the outer harbor must have been broken down and open to the sea. This high energy regime seems to have eroded out the initial harbor deposits that developed after the completion of the harbor in 10 BC. The locus indicates that the harbor was not a coherent structure by the 1st c. AD. This data is consistent with the discovery of a latter 1st c. AD shipwreck on the outer harbor moles and the 1st - 2nd c. AD erosional scour under one of the outer harbor caissons reported from previous seasons.

Locus 003 (Fig. 2) was characteristic of a clastic shallow littoral environment which changed to a lower energy lagoonal environment towards the top of the unit (Fig. 8) . This was evidenced at the base with a well sorted sand with increased silt/clay contents towards the top of the locus.  The evidence suggesting a well circulated lagoonal environment is provided by the in situ and articulated Ostrea on rubble from the middle of the locus which would have required water movement and limited sediment coverage to exist.  The degree of restriction increased towards the top of the unit as evidenced by the increased silt/clay content.  The restriction was probably caused by the formation of a sand bar across the mouth of the inner harbor (see Locus 002 below).  The formation of the highly restricted conditions of  Locus 002 happened suddenly since intact burrows and insitu bivalves were found at the top of Locus 003.  Pottery from this locus indicates that this environment occurred predominantly in the 2nd -3rd c. AD and may have extended into the 4th c. AD.

The overlying Locus 002 (Fig. 2) contained mud with variable portions of sand and organic matter which characterizes a restricted lagoonal environment with influxes of sand from storm activity (Fig. 8).  This interpretation is supported by the evidence of erosion of the mud and organic matter deposits and the lenses of coarser sand.  There is also a wide range of surface textures to the pottery.   Angular sherds were deposited directly into the lagoon and well rounded and encrusted sherds were transported into the lagoonal environment.  The high organic matter, seed and wood content in this locus also indicates a highly restricted lagoonal environment since this organic matter would require time to become water saturated in order to sink and be buried.  Based on the pottery dates this environment was present in 3rd to 4th c. AD and probably into 6th c. AD.  This highly restricted lagoonal environment formed either due to the formation of a sand bar across the inner portion of the harbor or through anthropogenic activity.  However, there is no surficial evidence to suggest that there was a wall restricting the inner harbor.  The sandbar hypothesis is a more plausible explanation and would probably have formed after the outer harbor breakwater had deteriorated.  There was probably an entrance channel that would have been dredged to allow ships to enter the lagoon.  This lagoonal environment must have been formed quickly since the upper portions of Locus 003 have remained intact (bioturbation structures and insitu bivalves).

The final unit in the stratigraphy of the inner harbor deposits was Locus 001 (Fig. 9) whose upper surface is also part of the modern environment (Fig.2).  The locus is characterized by a large quantity of rubble including marble and granite columns, large ashlars and a large quantity of intact pottery.  The very poorly sorted nature of the deposits, the large pieces of rubble, the wide range in pottery ages (although there is predominately 6-7th c. AD and 12-13th c. AD pottery), pottery types (cooking ware to transport amphora) and preservation (many intact and angular sherds without marine encrustation) and the abundant animal bone and metal artifacts in this locus could suggest that it was humanly dumped into the inner harbor.  This deliberate infilling might have been undertaken to prevent seaborn invasions after the Muslim conquest in the 7th c. AD.  A terrestrial dump or fill that was close at hand that contained predominantly 5-7th c. AD pottery could have been the source of infilling material.  The 11-12th c. AD pottery tends to be in the upper portions of this locus and their concentration in the inner harbor might suggest that harbor was still used in some form or capacity in these periods.  There is evidence of a wall (just east ofTN2; Fig. 1) that restricted the inner harbor that is laying just within the upper portions of Locus 001 which indicates that it was a post 6-7th c. AD structure.  There are also a large quantity of stone anchors found in this locus also suggesting the presence of maritime activity within the inner harbor during this time.

The 1997 inner harbor excavations clearly demonstrate the potential of integrating sedimentological, paleontological and archaeological data for the interpretation of ancient harbors.  The stratigraphic information from the excavations in the inner harbor indicates that the harbor was in a high energy state by the 1st to early 2nd c. AD and no longer provided a quiet water environment indicating that the outer harbor breakwaters were in a very poor state by this time.  The stratigraphic information also indicates that there was either an anthropogenic (seawall) or natural alteration (sand bar) of the harbor that created a quiet lagoonal environment in the 3rd to 4th c. AD and this location of the harbor was the center of harbor activity during this time.