The remains where they were found.
He hopes his inquiries, together with the help of the public, will help unravel the mystery of how the horse came to die in Samuel P. Taylor State Park, on California's north coast.
"It was found by a hiker about a month ago, in late November," Parkman told Horsetalk. The remains were stumbled upon by an off-track hiker in search of mushrooms.
It was only about 80 metres from the highway, but the steep, heavily forested terrain had kept the remains hidden all this time, he said.
He said the remains - he managed to retrieve about 80 per cent of the skeleton - were out drying in his driveway so they could be examined more closely.
The tack found with the horse includes a saddle, bridle and bit, lead rope, halter, and shoes - he recovered three - that hardly had any wear.
"It's a really interesting mystery," he says.
It would appear the horse was trying to make its way up the slope when it died. "Whether it broke a leg or got tangled up, we don't quite know that."
Animals attacked the carcass after its death, including what appeared to be a large predator, possibly a mountain lion, or several coyotes.
They were powerful enough to separate the head from the body. The skull was found about five metres from rest of the remains. "The halter was still with the skull, the bit with the body."
Parkman says his discussion with horse owners indicate the horse was a male and fully grown.
The bit carried the brand name Trammell, which was well known in Texas, he said.
He had been unable to identify a maker of the leather western-style trail saddle, although a saddle maker who viewed pictures of it believed it to be a Simco.
Parkman said his own measurements of the saddle indicated it appeared to have a smaller than average seat.
Those who had seen the tack agreed it appears to date from the 1970s. The archaeological evidence also fits that, he said. "It couldn't be too much earlier or later than that."
Parkman, who said he was doing most of the research in his own time, would like to think the horse could be identified and some light cast on how it met its fate.
"It died a lonely and tragic death," he said.
Parkman said he had been to New Zealand and knew how fond its people were of horses, as were Americans.
"Anyone who likes horses wouldn't like to think of a horse dying like that."
He would like to bring some closure to the case, he said.
Parkman said there were some unusual aspects to the find that add some mystery.
There was no saddle blanket and the halter had been put on backwards.
"I find them to be very interesting clues as to what happened. I don't yet know what it means. The last person to the ride this horse, were they a greenhorn? Or did they take it in haste?"
Records from the 70s have yet to turn up anything useful.
"We are talking to the police. We have not found anything yet."
Parkman undertakes archaeological work in 50 state parks, studying not only ancient finds but the likes of a 1960s hippy commune and a marine corps training camp from the same era.
He has a genuine desire to have the mystery solved.
"Horses are so loved in our countries," he says. "It strikes a cord with people. We will do our best to find out what happened."
Contact Breck Parkman (firstname.lastname@example.org) if you have information on this case.