W 30 (LY0757)
State: NJ
County: Sussex
Quad: Flatbrookville
Location: N 41° 05.733' W074° 55.733'
Elevation: 1002.13 ft.
Designation: W 30 1942
Setting: Round Concrete Monument
Type: Bench Mark Disk
Year: 1942
Established By: NGS
Searched For: 27 December 2006
Status: Not Found.
This was our second roadside-benchmark bummer of the day. (These are supposed to be the easy ones!) The description seems straightforward enough, but just in case, Rich and I came armed not only with the datasheet but also with coordinates we'd pulled directly from our USGS topo map, which tend to be quite accurate in my experience. But once at the site, we became frustrated. The configuration of the road didn't match the datasheet measurements, and try as we might, we could not understand how we could be simultaneously 35 feet NE of the centerline of the road, 35 feet NW of the stream, and anywhere near the coordinates. We searched the areas around both the datasheet coordinates and the map coordinates without finding any signs of a survey mark. The blazed trees and the reference post, of course, were nowhere to be found either. After a lengthy search we decided to move along to the next mark in the series.
Interestingly, a peek the next day at the historic topo maps on Maptech's website gave us a partial answer. The road curves toward the northeast, coming very close to the benchmark, according to the 1954 map (surveyed in 1942, the same year the mark was set). But by 1992, the road has been straightened; the new route of the road shows in purple on the most recent topo map, indicating that it is a new revision made from aerial photos taken in 1971. The straightened road no longer passes within several yards of the benchmark coordinates.
This information only settles the discrepancy between the datasheet measurements and the layout of the area as we encountered it. We still might have been able to locate the benchmark somewhere in the area we searched. It's possible that the entire area has changed dramatically and the mark may be deeply buried or even gone. If we're in the area again on a warmer, more pleasant day, we may attempt to search once more.
Zhanna
NGS Official Description, 1942 (see datasheet for recent updates) :
DESCRIBED BY COAST AND GEODETIC SURVEY 1942 2.8 MI E FROM FLATBROOKVILLE. 0.3 MILE SOUTHWEST ALONG A BLACK TOP ROAD FROM THE POST OFFICE AT FLATBROOKVILLE, THENCE 0.7 MILE SOUTH ALONG A GRAVEL ROAD, THENCE 1.8 MILES EAST ALONG A ROUGH GRAVEL ROAD, IN THE WOODS, 35 FEET NORTHEAST OF THE CENTER LINE OF THE ROAD, 35 FEET NORTHWEST OF THE CENTERLINE OF A SMALL STREAM, 16 FEET EAST OF AN 8-INCH TRIANGLE-BLAZED MAPLE TREE, 6 FEET NORTHWEST OF AN 8-INCH TRIANGLE-BLAZED OAK TREE, AND 2 FEET SOUTHWEST OF A STANDARD REFERENCE POST. A STANDARD DISK, SET IN THE TOP OF A CONCRETE POST.
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...1954 topo map ... road curves toward BM. |
...1992 topo map ... road has been straightened. |
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