For those interested, some cut & paste research

from the LCSCA FAQs. I left the formatting as is
In 1921, Charles Askins wrote in
The American Shotgun"It remained for America to have the final word in bolting mechanisms. Lug bolts located on or as part of the barrels were in the wrong place.
The hinge-joint of the barrels acts as a fulcrum of a lever, upon which, the barrels rest and pry at the bolts. It takes three times as much strength in bolts,
to withstand the pressure if they are placed an inch from the joint, as it would should the fastening be accomplished three inches further away.
Alex Brown moved his locking bolts from the lug and placed them in the extension rib, which is undoubtedly the right position for them mechanically.
Throughout the world no other locking devise should be used on a shotgun save the rotary bolt."
Me
The whole world had not taken Askins’ advice at that point in time, but some
form of primary or secondary top fastening system was used by Westley Richards,
Greener, Rigby, and Beesley in England, Merkel and most German-Austrian
makers, the Manufrance Ideal, and in the U.S. by L.C. Smith, D.M Lefever,
William Baker designed Ithaca and later models, Baker and Hollenbeck designed
Baker Gun & Forging guns, Remington 1893 and 1894, and A.H. Fox.
Chapter 15 of
Shotgun Technicana by Michael McIntosh and David Trevallion
discusses "Top Fasteners" specifically the Alexander Brown patent, and the
almost identical Ansley Fox patent.
"The most basic principle in fastening any hinge is that the farther the fastener
is from the hinge itself, the greater the mechanical advantage. That’s why door
latches are placed where they are. In a gun, the action bar and breech face
form two sides of a right triangle, so that the top or the breech face is farther from
the hinge pin, in straight-line distance, than the bottom. In a side-by-side gun
there’s an additional advantage in that a top fastener is a bit more efficient in
overcoming the effects of barrel flip-for the gun, if not for the shooter. With a
top fastener, the barrels still flip downward on firing, but the action bar flexes less,
and the fastener keeps the top of the barrels from pulling away from the breech
face."
"The most interesting of the American top fasteners is the L.C. Smith’s patented
by Alexander Brown in 1883. Where all the others used either Greener’s
transverse bolt, some sort of flat bolt or hook on the front end of the top lever,
or both, Brown designed his bolt as a steel cylinder that turns on a horizontal axis.
A slot filed into the cylinder forms the actual hook, which fits into a slot in the rib
extension. The cylinder also engages a lip at the rear of the extension as a
secondary bite. L.C. Smith described this arrangement as a double cross-bolt,
although double rotary bolt would be more accurate."
They also discussed some disadvantages of the rotary bolt, with examples of
actions shot loose with time (and magnum loads), but did agree that "...the top
fastener mechanism…makes excellent sense."