Dear Ms. McKeithan,
Thank you for posting your request on History Hub!
The National Archives and Records Administration (NARA) is the depository of the permanently valuable non-current records of the United States Federal Government. Under Italian law, records of births, marriages, and deaths are maintained by the Registrar of Vital Statistics (Ufficio dello Stato Civile) in the city (comune or municipio) where the event occurred. We suggest that you search Antenati: Italian Digital State Archives, the FamilySearch index for Italy, Matera, Civil Registration (State Archive), 1809-1925 and/or contact the appropriate Stato Civile for guidance on how to obtain the emigration records and other information that you seek about Marcus Mauro. Please review the FamilySearch Research wiki for Matera, Basilicata, Italy Genealogy.
You also may wish to search Ancestry, FamilySearch, and newspaper archives for mention of Marcus Mauro. There may be a fee for using these services. Instead, you may wish to contact your local library. Many library systems subscribe to these sites, making them free for patrons.
We hope this is helpful. Best of luck with your family research!