These studies of Roman capitals are fine little treasures to me. The first is an elaborate rendition of what is essential a Roman Composite Capital at the Temple of Mars Ultor in Rome. Due to its rich detail, I have to believe it was in the interior of the Temple where the fine little edges and protrusions were not directly exposed to the elements. It offered the sculptor much creativity. The Pegasi are assuming the place of the volutes and the Angel is assuming the place of what I call the secondary volutes in the middle. Angels figured now and then in pagan, pre-Christian Roman Art. Their wings indicated their divinity, like the winged medusa.
In the same picture, below the capital is what I assume to be the base of the same column. It is an Ionic base which is the most elaborate form. Naturally, the tori and astragals are heavily enriched.
The second picture is of a composite capital and a Roman Ionic capital, respectively. The name, 'Composite Capital,' is a modern invention. We do not know the named which the ancient Romans used for this type of capital. It revisits both the Corinthian and the Ionic capitals. It was used often in the basilicas of the high empire and in frigidaria which were derived from the same basilicas as a kind of truly colossal column to hold up the great cross vaults of the interior.
I have not yet modeled one, but I suspect it is somewhat easier than a Corinthian capital. As a young person, I liked it more than the Corinthian. Like the Corinthian columns of the high empire, the Composite column is also ten measures (or rounds) tall.
The Ionic Capital is definitely in the Roman style and richly elaborated.
The first picture I got of the internet and I'm sure the copyright has long since expired.
The second one is from the artists of the Grand Prix and also is long after its time.