Hello again, Charles. The coins on the links that I posted are probably closer to your coin than the specimen from
WildWinds (below). As Pekka K suggests, there are many variations in the altar-contours on these lesser
AEs from Nicaea depending on either the flan-shape or state of the dies (now and then, perhaps both), not to mention the wear on particular specimens
still exant. It so happens that this
Caracalla reverse isn't flagged in
RG, but it's flagged for the rest of the family (they shared such reverses), and
his version is not that uncommon;
acsearch for words "
altar" "nicaea" turned up two Caraacalla examples,
https://www.acsearch.info/search.html?id=3963886 and
https://www.acsearch.info/search.html?id=502455. As I stated, the laureate-radiate
obverse went apparently unrecognized till this very discussion on
Forum; apart from the
Weiser catalogue of Bithynian coins housed in Koeln, you'd be hard-pressed to find a more helpful supplement to
RG for Nicaea than our website's "Nicaean Addenda." To the best of my knowledge (and I've paid some attention), "
Lowe 222" doesn't point in a meaningful way to any
catalogue you can make use of.