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Thursday, 6 January 2011

Impact Crater in New Mexico – Part 2 Lincoln County Revisited

Impact Crater in New Mexico – Part 2 Lincoln County Revisited

In Impact Crater in New Mexico – Part 2 Lincoln County at

Rob, about the features in 34° 0' 51.00" N 105° 8' 41.46" W
( 34.0142° N, 105.1448° W ) commented,

“Looking at these features in Google Earth, they appear 
to be capped limestone structures rather than depressions. 
Has anyone on the discussion list actually been there?”

I consulted the USGS topographic map and the 10-m DEM 
for the Cowboy Mesa SW 7.5 minute quadrangle. They
both show that these features are depressions and that 
they are certainly not limestone capped hills. Depending 
on how a person’s brain interprets the shadows, images 
on two-dimensional aerial photographs can appear to be 
either depressions or hills. Because of this quirk of how 
the brain works, it is useful to consult either topographic 
maps, digital elevations models (DEMs), or stereo pairs 
of aerial images when making interpretations.

Similar depressions can be seen elsewhere in the
regions in aerial photos and topographic maps. 
Similar depressions occur in Sections 29 and 28 of 
T. 4S., R. 17E. at 33.936° N, 105.179° W. This is 
about 9 km south-westsouth of Guenther’s depressions. 
Even more depressions can be seen about 32 km to 
the west – west-southwest in Sections 1, 2, 12, 20, 
21, 22, 33, 34, and others of T. 4S., R. 14E. Examples
of other similar depression can be found at 33.988° N,
105.435° W. and 33.946° N, 105.479 W. They all have 
the typical morphology of sinkholes. The typical
morphology of sinkholes as seen in topographic maps 
is discussed by Miller and Westerback (1989).

By the way the correct location for Guenther’s depressions 
is S1/2 of the SE1/4, of Section 27 and the N1/2 of the 
NE 1/4 of Section 34 of T. 3S., R. 17E. I mistakenly wrote 
“NE 1/2” instead of NE1/4”.

These posts are in reference to “Impact Crater in New Mexico” at

and “Impact Crater in New Mexico – Part 2 Lincoln County”

Reference Cited,

Miller, V. C., and M. E. Westerback, 1989, Interpretation
of Topographic Maps. Merrill Publishing Company, 
Columbus, Ohio. 416 pp. ISBN-13: 978-0675209199


Paul H.

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