LIDAR Magazine

Pelham’s Instructions

The following is a letter of instructions to Deputy Surveyor John W. Garretson for the survey of the Initial Point, Principal Meridian and Base Line. I have condensed the text by 40%. Those who so desire can obtain a copy of the handwritten original from the editor of BENCHMARKS.

Surveyor Generals Office
New Mexico March 9th 1855

Sir,

In the execution of your contract of this date, to survey the Base and Meridian Lines, as a basis for the public surveys of the Lands in the territory of New Mexico, you will provide yourself with a Burt Improved Solar Compass having a telescope attached: also two two-pole chains of fifty links each, and eleven iron or steele [sic] tally-rods, having heavy steele points, that may be used in plumbing while chaining uneven surfaces…. One of your chains, after they shall have been adjusted to the standard measure of this office, you will carefully preserve, and prevent its becoming rusted or used for any purpose except to regulate the one in active use. This you will cause to be compared and adjusted to the standard as often as once a day while you are at work.

As you are aware that most errors in surveying are caused by inaccuracies in chaining, and a rigid accuracy is required both in the measurement and surveying of those important lines, you will be careful to employ no assistant who is not competent and trustworthy as chainman or flagman…. You will also employ one spademan and an axeman, with a sufficient number of hands to enable you erect the mounds and corner posts in excellent order and with facility.

After you have prepared for your expedition, you will repair to the mouth of the Rio Puerco, a small river, a western tributary of the Rio Grande del Norte, where you will make a reconnaissance of the adjacent country, and select the nearest suitable site, on firm ground, for the erection of an enduring monument to perpetuate the Initial Point of the public surveys in New Mexico. You are especially instructed to erect the Initial Monument of rocks, should you find any in the vicinity, but in case there are none to be found, you will erect it of earth and sod, having charcoal placed at its base, upon which the Monument will be constructed, and also having a large stone, not shorter than two feet, and not smaller than two inches in size, placed in its centre, at the top….

From this point you will observe for the latitude…. and run a line south for a Principal Meridian, taking care to mark corners or erect monuments for quarter section, section, and township corners…. You will prolong this line South until you intersect the Southern Boundary of New Mexico: provided that your Meridian shall be on the West side of the Rio Grande…. But, if in the prosecution of your work you shall ascertain your Meridian not to be on the West side of the Rio Grande, when approximating to the Southern Boundary of New Mexico, you will at your discretion suspend operations until the boundary between New Mexico and Texas shall have been established.

After you shall have accomplished the extension of this line, you will return to the Initial Point and survey the Meridian North from said monument as a Principal Meridian….

After you shall have accomplished the survey of the Principal Meridian Line you will return to the Initial Monument and run a line West on that parallel for a Base Line…. You will continue this line as far West as you may deem the public service demands at the time. Having accomplished this survey, you will return and do likewise East of the Initial Monument….

You are aware that substantial and enduring evidence of corners are important objects of the survey and if you fail to erect such the purpose of your labors will have been in vain…. The Manual is deemed sufficiently explicit and comprehensive to embrace every case that may arise….

Very Respectfully
Wm. Pelham
Surveyor of the Public Lands in New Mexico

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