Baptisms in this era often only had the name of a father. If the child was born in wedlock, the father was listed. If it was illegitimate the mother would be shown, but in some areas it is unusual to find both parents listed. You will not be able to find the name of the mother from any other record. The only thing you can do is try to find a marriage of the father, and hope that the wife, is the mother of the child. It is a bit of guess work unfortunately.