Early American Imprints (also known as Evans) -- This microcard collection, which is kept on the bottom floor of the library near the microfilm cabinets, reprints documents from early American history. The index to it, called the American Bibliography, is located on a small bookshelf near the Early American Imprints.
Also look for:
Colonial Records of ....(Various states) -- Use IDS Search to find them by title or use the subject heading "colonial period sources" and then the state name.
Narratives of Early American History -- This multi-volume series can be found using IDS Search.
You will get limited results if you try to search for "primary sources" in library databases since the Library of Congress does not use that subject heading. Try searching these subject headings instead: