hi again epighany,
Do you have the marriage cert for Dorethea Anderson-Gross and David Anderson? This will give you her father's name then it might be possible to trace his marriage to Cora, if they married.
We can then trace them through the US fed census up to the latest census available (1930), bearing in mind that unfortunately the 1890 census was mostly destroyed.
When posting a request please add the place they were born and where you expected them roughly live. It helps RC helpers enormously in the search!
I'm not sure if you know, but the US BMD (vital) records work in a different way to ones we have here in England. In England, after registering a BMD in the local registrars office, the data is then collected in a central deposit which we call the GRO. We can then apply to the GRO for a copy of the relevant cert.
In America and Canada, each state has its own vital records office (you can find it by googling the state or town + vital records). They are not centralised anywhere and there are no indexes published on the web
Once you have an approximate date and place, you apply to the state vital records office. I believe you were given the link earlier in this thread for the one you were looking for.
www.familysearch.org has some baptismal/marriage/burial records but it does depend on the religious denomination on what is held and each state varies on how much data is on familysearch.
