You haven't posted a message on our Entwistle Family History Association website, but I've now found out why my message didn't go through, so I've made some changes and I'll try again.
I've checked, and the marriage in 1872 appears to be the only one between an Alice Entwistle and a Samuel Baldwin around that time. Joe gave you all the information you need to order a copy of their marriage certificate, i.e. 1872, June - September quarter, Bolton Registration District, volume 8c, page 473. You order this on-line by credit card from the GRO, which is the General Register Office, and the information has come from their Index of Births, Marriages and Deaths. Their website is: www.gro.gov.uk
As Joe said, the certificate will give you the names of both fathers, and their occupations, and also the ages of Alice and Samuel when they married. This information will be of help when you come to look for Alice's birth certificate, which will give you her mother's name.
Dot Stutter has suggested that you join the Entwistle Family History Association. I am the Chairman and Research Co-ordinator, and keep all our Entwistle data, so may be able to help you once you have more information. Check out our website: www.entwistlefamily.org.uk