Here ends my first review of the ancient maps. What has it learned us?
It suggests that Ptolemy (c. AD 90 – c. AD 168), was aware that you could sail "through" Cephalonia. His charts are lost and some of the 16th century remakes present a nonexistent island southwest of Cephalonia. The mysterious Piri Reis drew, in 1512, an accurate map with a scientific basis that presents an isthmus near Paliki and a second isthmus further East. In the middle of the isthmus is a significant land mass.
Renaissance cartographers clearly did not know how to handle the situation. Consequently they went through a process of presenting “best” solutions:
1. Follow Pliny the Elder and Ptolemy; map islands West or Southwest of Cephalonia.
2. Interpret Piri Reis; map a Channel straight through the mainland of Cephalonia. Too far East and geotechnical very improbable.
3. Implement more detailed renaissance geographical knowledge, but exaggerate the coastal indentations as to suggest the presence of a lost Channel.
4. Finally, everybody agrees to ignore the myth of Schizocephalonia, because the Channel is just not there... anymore.
Furthermore we learned details. The ideas of the Author on the island Asteris proved realistic. This area has seen a lot of change over the ages and the present capes are the islands from the past.
The stone walls in the lower parts of Northeast Argostoli Bay are remainders of salt evaporation ponds, built for extracting salt from the sea. It seems an excellent reuse of a harbour that has become too shallow. It will be interesting to check them for the presence of old anchor stones.
Further information will have to come from older, pre-renaissance, sources or from modern research. My interest has been raised and I look forward to visiting the area with my sailing boat later this summer.

I hope you found my contribution of interest and await your comments.
Best regards,
Marinus
Maps presented with kind permission of the Samourkas Collection. The text of this post has been edited various times after the date of posting and after the reply of Demodocos.