Stories set in Colonial Virginia / New World with magical secrets in the wilderness

Question

I am trying to identify the author of a series of paperback SF books I read back in the 80's. The stories were written in the 80's or in the late 70's. (Or maybe I am remembering that wrongly).

The conceit was that a place like actual colonial Virginia was being settled (something like a few decades after the founding of the Jamestown colony), there was tobacco farming involved, and indentured servants. I think that the largest settlement was along the coastal plain. There was exploration to the mysterious and magical interior in the woods and mountains of what was obviously colonial era Virginia (1600's) with blunderbuss, musket, etc.
I vaguely recall some puritan religious sorts mixed in somewhere.

At one point, some of the major characters went into a mountain and magical stuff began to happen. I never found the next book, though.

I could swear that the author is named Angus {something scottish} but my internet searches to date are not working. And I also might be recalling the name incorrectly.

Who wrote these speculative fiction/fantasy novels?
What is the name of the series?
I can't find any of them up in my attic with all of my old Conan and Elric books, so I either lost them, donated them, or turned them into second hand books a few decades ago. It's killing me.

Answer 1

I suspect this is the Alvin Maker series, by Orson Scott Card.

I haven't read these books, but according to Wikipedia:

The stories take place on the American frontier in the early 19th century, a fantasy setting based on early American folklore and superstition, in a world in which many characters have a limited supernatural ability, or “knack,” to do some task to near-perfection.

The stories involve a number of historical events and figures, but as a creation of alternate history. What was documented as the Colonial United States is divided in the books into a number of separate nations, including a smaller United States. It displays much stronger Native American influence in its culture and society between New England and Virginia and extending westwards to Ohio. (New England is a colony of a Republican England where the Restoration never occurred.) A monarchy on the southern portion of the Eastern Seaboard (where the real-world Carolinas, Georgia, etc. are) known as the “Crown Colonies” was founded by the House of Stuart in exile. In addition, many of the historical figures are either presented as caricatures or bear only superficial resemblance to their historical persons.

This is a couple centuries later than you recall, but it's the right kind of stories, by an author with an Irish-sounding first name, and it's a series, the first three novels were published in the late 1980s, and there are at present six titles with a seventh (Master Alvin) listed as forthcoming.