diff --git a/lib/Bastion/Packers/TARs.py b/lib/Bastion/Packers/TARs.py
index 7ded4ce..473de1b 100644
--- a/lib/Bastion/Packers/TARs.py
+++ b/lib/Bastion/Packers/TARs.py
@@ -11,6 +11,7 @@
 
 from Bastion.Common import *
 from Bastion.CARP import ReportException
+from Bastion.Chronology import 
 
 logger = logging.getLogger(__name__)
 
@@ -192,4 +193,17 @@ def unpack(self, halo, root, **kwargs):
 		raise NotImplementedError
 
 
-
+def catalog(tarp):
+	"""
+	I answer the catalog of a tar file at the given path, tarp.
+	The catalog is a list of entries of the form (size, modified, path)
+	where size is in bytes, modified is the quantim of the file's mod timestamp, and path is a pathlib.Path object
+	"""
+	cats = [ ]
+	with tarfile.open(tarp) as tark:
+		for info in tark.getmembers():
+			sz = info.size
+			mq = quantim( datetime.datetime.fromtimestamp(info.mtime) )
+			pt = pathlib.PurePosixPath(info.name)
+			cats.append( (sz, mq, pt) )
+	return cats