I can find the odd pebble in the chalk,rafted out to sea and entombed for 65 million years,often though they seem to be glacial morraine as an infill in fissures in the lower upper chalk as the upper upper chalk was sheared off the locality during one of several periods of glaciation.
Looking at the local quarry walls there are pockets of brown dirt eroding out of the galleries,it's off limits so i cannot get to examine them for contents,these extend the the lower reaches of the pit and presumably represent the middle chalk.
Could each of these represent a rafting or maybe the fissures run quite deep?
Anyhow,these are the only hardrock geology in the area so getting rid of iron staining,calcite and glauconite from specimens is a must as incomplete diagenesis is unnatractive.
Flint nodules are unnatractive too.