Here's another mini case study that shows the sort of information that excavation can develop. The marker in question was an old piece of 1/2-inch iron pipe. The photo below shows how the marker looks at the surface. It's in contact with an old telephone service conduit seen running approximately horizontally.
There is a question as to whether that particular pipe is an original marker from 1940 when the subdivision was laid out. The top of the pipe was only 7 inches below grade and other original markers nearby were considerably deeper, lying under the fill from street construction. So, with the total station we carefully located the pipe as found and got to work with the high-tech device sold commercially as a "shovel" or "spade".
The pipe looked fairly beaten up on its top and showed a bend just a few inches down, so I thought it would be worth digging down to the level of the native soil to see if the pipe had actually been set in the road fill. A plumb bob string provided a useful way to show how significantly the pipe leaned.
The native undisturbed soil was about 27 inches down, it turned out, and the pipe was only 10-1/2 inches long.
There was some question as to whether the pipe was of recent origin or not. Examining it showed that it had fairly heavy surface rust and that it was adhered to the base material in the road fill. I'd say that it had been in the ground a good while, possibly for decades.
Yes, we put the pipe into the exact 3-dimensional orientation in which we found it and, yes, the center of the top is essentially exactly as found, same horizontal and vertical position.
Kent-
Good one!
Derek
PS-
Is this a new Photoshopper ?
There's no crystallized water vapo(u)r to be seen !
Are you using one of those fancy anti-gravitational brass instruments for a string line to give a visual bearing on what your looking at? I tell ya, first a shovel and now a plumb bob. Whats next, a steel tape? I guarantee these young bucks don't even have any clue about a plumb bob!
> There's no crystallized water vapo(u)r to be seen !
Derek, we actually did have one day of snow in Central Texas. It was fun. And then it melted. The highs will be in the upper 70's and lower 80's for next week's field work in West Texas. I'll be sure to post a photo or two for the benefit of the subarctic readership.
> Are you using one of those fancy anti-gravitational brass instruments for a string line to give a visual bearing on what your looking at? I tell ya, first a shovel and now a plumb bob.
Yes, I called it a "plumb bob string" just because many old-timers will think that's what it is. It performs a similar function, but it actually is a Real-time Nadir Sensor with Interactive Counterharmonic Damping. Very high technology solid-state device.
