Jim Elbrecht wrote:
[sni]
> Which end of the pig are those butts coming from? I would expect a
> butt to be from the hindquarters of a critter-- thus 'buttocks' and
> 'rump butts'. Any diagrams showing the butt coming from a
> shoulder?
>
[snip]
From: Military Meat and Dairy Hygiene prepared under the
direction of the surgeon general of the United States Army.
United States Surgeon-General's Office, Horace S. Eakins.
Williams & Wilkins, 1924, pp. 209-210.

"A Boston butt is the lean portion of the shoulder plus some of
the fat, after the clear plate is removed. It is about two-thirds
lean and one-third fat, and also contains a portion of the scapula."

But does this contradict the above:

"This side of pork is from one of the animals used in the judging
ring yesterday. I will cut this up, showing the different cuts as
we would cut it if going to cure the shoulders as pickled hams and
going to cure the hams, showing the different cuts made in
trimming up these shoulders and hams, making the loin to be sold
out as loin from the retail shop.

"First, take off the shoulder, cutting as I have cut this one back
of the fourth rib. This is not necessary. If you want to make a
heavy shoulder you cut further back and for a lighter shoulder you
cut only three ribs. Up at State College we have been just
starting some experimental work in curing hams and shoulders and
cutting them up the same, cutting them between the fourth and
fifth ribs, and cutting that way you notice this shoulder would be
trimmed out and the first trimming would be to take out the spare
ribs, cutting close to the bone. That gives you what they call
butcher's spare ribs. It is very thin spare ribs, of course, used
for packing up and roasting. It is quite a choice cut but not cut
heavy like what we call farmers' spare ribs. The next cut will be
to cut off the shoulder butt, right across the top, about
one-third the top, what the packer would call the shoulder butt.
The top across the top of the shoulder blade. This would be called
a shoulder butt. Trimming off the fat we would have the fat
separated like this. It is called the clear plate. This plate or
piece of lean taken out would be called the clear plate and that
is used by the packers and cut up into chunks, put down in salted
brine and shipped to foreign countries and also somewhat used in
this country for certain classes of trade in the mining and
lumbering districts, and it is known on the provision market as
clear plate. Ordinarily the farmer would simply trim that off, of
course, taking off the rest of the lean and use it for making
lard. This lean portion that is left from the shoulder fat is
practically all lean meat and makes a very nice roast, or if
sliced across this way, crosswise, about one-half inch wide, about
the thickness of pork chops it makes a very nice steak and is
called "Boston Butt" by the packers...."

Annual report of the Pennsylvania Department of Agriculture,
Volume 16 (1911): pp. 535-???.

You can see a pic he

<http://books.google.com/books?id=lQhIAAAAYAAJ&pg=RA2-PA43&dq=%22Boston+butt%22&hl=en&ei=k1YFTre5FYTegQe 80fS3DQ&sa=X&oi=book_result&ct=result&resnum=8&ved =0CFEQ6AEwBzgK#v=onepage&q=%22Boston%20butt%22&f=f alse>


or:

http://tinyurl.com/6f5rk7h

I have to scroll up a wee tad to see the complete photo.

--
Jean B.