The Preservation of Invertebrates in 16th‐Century Cesspits at St Saviourgate,York*

The taphonomy of invertebrates from 16th‐century cesspits at St Saviourgate, York, was investigated. Earthworms, fly larvae and puparia are preserved through replication in calcium phosphate, a process facilitated by acidic cesspit pore water and by the presence of abundant organic matter, bones and shells. Features preserved by mineralization include muscles, blood vessels and setae. Non‐mineralized invertebrate remains include puparia and beetles. Py–GC/MS (flash pyrolysis–gas chromatography/mass spectrometry) revealed a very high level of preservation of structural biomolecules, with all the protein and chitin markers that are evident in the living forms still being detectable in the divalent remains.     

X‐RAY SUB‐MICRON TOMOGRAPHY AS A TOOL FOR THE STUDY OF ARCHAEOLOGICAL WOOD PRESERVED THROUGH THE CORROSION OF METAL OBJECTS

Wood preserved in the corrosion layer of two early medieval iron objects was examined using X‐ray tomography. A state‐of‐the art multi‐resolution X‐ray tomography set‐up ( http://www.ugct.ugent.be ) provided virtual cross‐sections of the archaeological wood samples at sub‐micron resolution. These were compared with scans of samples of similar modern wood. These scans demonstrate the power of sub‐micron X‐ray tomography for wood identification, although the process of mineralization pushes this technique to its limits. Furthermore, this technique facilitated appraisal of the mineral content of the archaeological wood, which is useful in selecting the most appropriate strategy for the (preventative) conservation of the archaeological object.