The $17.50 cert one downloads from Vic BDM appear to be scans from the original registers. I have one full page of Births from Geelong, 1880, which has five births detailed. Of these, three Informants (including my g-g-grandmother) have signed with a Mark. Of the two Informants who have actually signed, one is the baby's 10 year old sister. All the details on the page have been written in the same hand (beautiful writing, but so tiny!), with the signature of the Deputy Register in different handwriting. It would seem that the Registry Office clerk asked the Informant for the details, wrote them up and then turned the book over to the Informant for signature, or mark, the clerk then writing the name around the Mark. I'm not sure my g-g-grandmother could spell either. Our surname is spelt in a variety of ways on earlier registrations. Barbara