Rocky Mountain High – Finding the Western end of the 6th PM Base Line

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Finding a small chiseled cross established 147 years ago and 21 miles deep into Colorado’s Front Range of the Rocky Mountains would be the ultimate challenge. That challenge was met by seven determined men after six months of research, planning, and calculations that culminated in a rewarding quest to find this important location.

In the late 1850s the Base Line for the 6th Principal Meridian surveys was slowly progressing westward between the Territories of Kansas and Nebraska. The normal procedure while establishing this Base Line was for the General Land Office (GLO) to award contracts in stretches of 48 miles between guide meridians. The westerly guide meridian would then be run north and south, standard parallels would be extended west, and the townships and subdivisions would soon follow. The GLO was in a relative state of calm after dealing with the unforeseen rush of settlers across the Missouri River in 1854 when the two territories were created. The situation of thousands of squatters in the Public Domain combined with the first 108 miles of the Base Line being erroneously marked upon the ground was now in the past as the Base Line reached its 204th mile along Latitude 40 North. The calm was shaken with the discovery of gold in the Rockies near Black Hawk-Central City, Kansas Territory, and almost simultaneously near Gold Hill, Nebraska Territory, in the spring of 1859. Word of the discovery quickly spread and within weeks an estimated 10,000 people had rushed to the unsurveyed area to seek their fortune. Matters were further promulgated by a former U.S. Deputy Surveyor from Omaha named William N. Byers, who founded the Rocky Mountain News in Denver in April 1859. With his flamboyant style of writing, Byers depicted the entire area as a treasure land teeming with gold nuggets just waiting to be picked from the surface. The GLO once again found itself in a situation of great concern since the public land surveys were still an estimated 400 miles from the new gold fields.

On June 10, 1859, Contract No. 276 was awarded to U.S. Deputy Surveyors Jarret Todd and James Withrow to extend the Base Line to the Rockies. It was the highest price paid per mile to any crew surveying in the Kansas and Nebraska Territories up until that time. At $30 per mile, it was 2 times more than U. S. Deputy Surveyor Charles A. Manners had been paid to establish the first 156 miles of the Base Line, set the Initial Point, and also survey the entire length of the 6th Principal Meridian in Nebraska at $12 per mile. The remainder of the Base Line would go directly into known hostile Sioux Indian territory, and the field notes were required to be in the hands of the GLO by the end of the year.

Both Todd and Withrow were experienced surveyors. Withrow had surveyed in Wisconsin in 1854 before moving to Kansas the following year. Both he and Todd surveyed together in 1855 before Withrow moved into Nebraska to survey townships and standard parallels for the next three years. Withrow’s expertise was operating the solar compass, which was a prerequisite for running the curved lines. Jarret Todd had stayed mostly in Kansas where he subdivided townships, as did his brother Green D. Todd who had worked in both Territories.

Coming together again in 1859 to survey the remainder of the 6th Principal Meridian’s Base Line would be the culmination of both men’s careers. As both surveyors were assembling their combined crew, another U. S. deputy surveyor named Nathan P. Cook was surveying 48 miles of the Base Line between the 1st and 2nd Guide Meridians West during June 1859. When Todd & Withrow arrived at Cook’s final corner on July 18, 1859 204 miles west of the Missouri River they discovered that the corner and the four surrounding witness stones had been completely obliterated. They suspected Indians, which likely caused concern for the crew members who were without a military escort. Two other U. S. deputy surveyors were also part of the group in non-leadership roles. William H. Godwin was likewise experienced with the solar compass, and Frederick Hawn, although not mentioned in the notes as being with the 12-man crew, accompanied them out of curiosity as a geologist. For expedient reasons, the Kansas/Nebraska Territory Surveyor General Ward B. Burnett hired Todd & Withrow after Charles A. Manners had submitted an exorbitant price of $35 per mile. Those in Washington, D.C. had recommended famed U. S. Deputy Surveyor Henry Washington before learning of Burnett’s decision. By the first day of August an allegation was received at the Washington, D.C. office that Jarret Todd was not a surveyor, and could not even add up a simple column of numbers. Although Withrow was likely the brains behind the operation, Todd was indeed a competent surveyor. Surveyor General Burnett sent a series of letters to Washington providing references and credentials on Todd’s behalf to soothe their fears.

The crew progressed across the open plains averaging just over seven miles per day. After leaving the Missouri River, the Base Line had drifted north and was about seven seconds of latitude north of 40 latitude at the Initial Point located 108 miles west. By the present-day location of the corner common to Kansas, Nebraska, and Colorado, the line was more than twelve seconds too far north or just over 1200′ too far on the ground. It was in this area that corrections were evidently made and a long taper was begun to bring the line back south. It is probable that the distance to the Rocky Mountains was estimated to adjust their calculations since the modern-day city of Boulder is at exactly 40 latitude on the Base Line. The crew reached the foot of the Rockies on August 31, 1859, after surveying 45 days and traveling 324 miles. Soon after starting into the Rocky Mountains, the Base Line began to drift slightly south of the parallel. The crew averaged about two miles per day in the mountains and reached what they thought was the summit on September 10, 1859, for a total of 345 miles, 29.04 chains from their starting point. They marked the supposed summit point with a chiseled cross and were instructed to also chisel "Utah" on the west face, "N. 40 L" on the east face, "Rocky Mountains" on the north face, and "1859" on the south face. In addition to these marks, a nearby rock witness mound was built with a base being six feet square and piled five feet high.

The summit mark in the Rocky Mountains established by Todd & Withrow defined the northwestern corner of Kansas Territory which also corresponded to the southwestern corner of Nebraska Territory. The significance of this mark for these two territories was, however, short-lived since two years later in 1861 both territories, along with Utah and New Mexico, were greatly reduced with the creation of Colorado. The chiseled cross did remain the western terminus of the Base Line until 1867 when U.S. Deputy Surveyor George H. Hill was awarded the contract to extend it westward.

When Hill’s crew of seven men arrived in the Rocky Mountains on September 25, 1867, the markings made by Todd & Withrow were not found on the Continental Divide, which would normally be synonymous with also being the location of the summit. Instead, the 1859 chiseled cross and rock mound were found on a high ridge which extended northeasterly from the Continental Divide. Hill used the mark established by Todd & Withrow and extended the Base Line westerly to the true summit on the Continental Divide a distance of 51.02 chains (3367.32′) before going on west. The true summit location established by Hill turned out to be just six links west of the location needed to set the corner common to Sections 32 and 33, T1N, R74W, so he placed a marked granite stone for the section corner and noted the distance to the summit without setting an additional monument. With the state boundaries of Kansas and Nebraska now located about 100 miles to the east, the summit at this time was no longer a significant boundary corner, but instead just a large topographical feature to be noted.

The Recovery Expedition
In 2006, the team that assembled to find this mark included seven representatives from three states, five of whom are licensed land surveyors. Representing Colorado were licensed surveyors Doyle Abrahamson and Geof Stephensen, along with USGS geochemist Pete Modreski who were all very familiar with the Rocky Mountains in the climb area. Representing Kansas was licensed surveyor Steve Brosemer, who has worked closely in remonumenting other significant corners on the Base Line. Nebraska Deputy State Surveyor Gene A. Thomsen accompanied Kurt Svodoba and me from Nebraska. In some respects it was an old-timers’ group with five men in their 50s and me being the youngest at age 40. However, the experience used to find this point and the determination to succeed more than made up for any physical age barriers.

While initially viewing the USGS quad sheets, we knew that the Base Line was most likely south of true 40 latitude and not on the Continental Divide. This search location needed to be narrowed down significantly in order to be successful in finding the mark left by Todd & Withrow. Doyle and Geof did a great job of locating and getting positions on other monuments east and west of the Continental Divide so a more defined search location could be determined.

After five months of preparation, we met on the evening of July 28, 2006, at a primitive campground along Boulder Creek a few miles west of Eldora, Colorado. Our gear, food, and water were loaded into backpacks that evening since our early morning wake-up was at 3:00 a.m. We then drove to an area known as the Fourth of July Campground and used headlamps as we started out on a trail at 4:20 a.m. After a few hours, we departed the trail and began our way through unmarked areas to reach the timber line. Occasionally we would get a glimpse of our goal far off in the distance; it seemed as if we would never reach it. Rest breaks were spaced approximately every hour as we increased in altitude and the air became thinner. Approximately 1,500′ east of the summit point, we paused to view the wreckage of an AT-6G aircraft that resides at exactly 40 latitude. The aluminum body is very well preserved and does not seem to indicate the December 14, 1971, crash date in which the solo pilot was killed.

The final climb up the steep rock-covered ridge required the team to spread out in case one of us accidentally started a rock slide. It was slow going, but the summit of the ridge marked by Todd & Withrow in 1859 was reached at 10:00 a.m. Using hand-held GPS receivers, we first located the remains of the rock witness mound on a ledge along the east side and just below the top of the ridge. The 1859 notes had stated a bearing of S 37 E and distance of 15 links from the rock mound to the chiseled cross mark. Although the mark was placed on the wrong ridge, the notes of Todd & Withrow did a very good job of describing that the "cross" would be located on "a towering granite rock reached with difficulty presenting a top so acute that a man cannot stand on it." The bearing and distance pointed exactly to such a location, but no marks could be found. After brushing away several very hardened layers of dried lichen the "cross" appeared about one tenth of a foot below the top and on the eastern face. We also found the initials "ACB" carved into the face of a rock wall west of the rock mound. An examination of the notes revealed that one of the crew members was Albert C. Bringhurst.

We spent about three hours at the site taking photos, obtaining a static GPS position, and documenting our important discovery. As our good fortune would continue, two hikers named Dennis Staley and Chris Smith happened to be climbing along that same ridge that normally does not see a lot of hikers. With their assistance, a group photo was taken of our team, posing behind the rock mound and around the granite containing the cross mark. Our return trip to the campground required nearly six hours of hiking, but the mountain scenery made the descent so enjoyable that no one noticed much difficultly, even with individual backpacks weighing up to 35 pounds.

Perhaps the foremost questions we surveyors were trying to determine is how and why Todd & Withrow had mistaken the ridge for the actual summit. The ridge that contains their cross mark extends approximately three-quarters of a mile to the northeast and abruptly ends, making it obvious that it could not be the true summit. Why, after traversing 21 miles through the Rockies, would they end one ridge too soon? The answer could be unveiled in a combination of factors. In their notes they stated that some of the gorges near the summit were up to 25′ deep with snow. They also stated that the higher peaks of the mountains were hidden from view by overhanging mists or clouds; otherwise, they would have taken bearings to the most prominent peaks. If September 10, 1859, had been a rainy or foggy day, it is possible that they could not accurately see that the ridge they were on ended to the northeast. Their marked summit location on the ridge is actually higher than the true summit location further west on the Continental Divide, so there may have been some confusion as to what was meant by "summit" if they thought it meant the highest reached point. Nowhere in their detailed instructions does it ever use the words "Continental Divide", but the instructions repeatedly use the word "summit".

Their summit point was established by triangulating from atop a mass of rock that is located directly south of the easterly end of the ridge. Since it requires at least a two-hour hike and climb from this location to the top of the ridge, it is possible that Todd & Withrow never actually personally set foot at this point, but rather just members of the crew were there who relayed the information that they had reached the summit. The true summit on the Continental Divide cannot be seen until you are actually on the ridge. There would have been no easy way to set upon the location of the cross mark with an instrument or to establish a triangulation baseline from it to continue measuring west. It would have required much difficulty to continue the Base Line to the true summit location; that would have perhaps created two more days in the field. The gold rush was likely luring many of the crew members, and the team perhaps said "close enough" and departed to collect their money and seek other fortunes.

After Todd & Withrow had finished the Base Line to the summit of the Rocky Mountains, collecting their pay of $10,360.89 became an equal challenge. Those in Washington, D.C. who had disagreed with Surveyor General Burnett’s decision to hire the pair demanded proof in written notes that adequate astronomical observations had been taken. Although the notes of Todd & Withrow state that the solar compass they used was periodically checked for accuracy, they had not been specifically instructed by Burnett to provide detailed notes, and therefore had nothing to present as proof. The last correspondence uncovered is dated February 24, 1860, which reveals the surveyors had still not been paid. The notes, however, of Todd & Withrow are the actual accepted notes for the Base Line, so at some point they must have been approved after a field examination.

On August 19, 2006, members of the Professional Land Surveyors of Colorado (PLSC), Inc., led by Doyle Abrahamson and John (JB) Guyton, President of PLSC, Inc. hiked to the location of the true summit set by Hill in 1867 in the hope of finding that point. The narrow ridge along the true summit is completely void of stones in the area where the section corner and accompanying mound of stones should have been. It was conjectured that over the years hikers had likely thrown rocks over the side in an attempt to see if they could possibly create a rock slide on the steep eastern face. Members of PLSC, Inc. have remonumented that lost section corner location on the True Summit of the Rocky Mountains.

The Base Line for the 6th Principal Meridian is the longest baseline in the continental United States. Its terminus is now the western boundary of Colorado and the significance of the chiseled cross set high in the Rocky Mountains in 1859 might seem irrelevant today, unless you are a surveyor looking for an adventure.

Jerry Penry is employed by Lancaster County Engineering in Lincoln, Nebraska. He has been a licensed surveyor since 1994 specializing in section corner monumentation and GPS surveying. He is a regular contributor to TAS.

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About the Author

Jerry Penry, LS

Jerry Penry is employed by Lancaster County Engineering in Lincoln, Nebraska. He has been a licensed surveyor since 1994 specializing in section corner monumentation and GPS surveying. He has presented surveying seminars with a historical aspect combined with modern day application. His special interests in this field include extensively researching historically relevant information, making the original surveyors' work come alive. His meticulous research and thorough writing sheds light on the original surveyors' tools, conditions and limitations. He is also very knowledgeable in various other historical matters including railroad history. He has written numerous surveying articles for newsletters, magazines and journals, and has authored or co-authored several books including The Chicago and North Western Cowboy Line: A History of the Longest Rail-to-Trail Project in America, and The Sunrise Serenade: A World War II Bomber Crew Story. Contact Jerry Article List Below