Haystack: Is it a Volcano?

Standing rather proudly in the shadow of the Rocky Mountains along the front range of Northern Colorado is a very unique little mountain affectionately known as Haystack Mountain, earning its name by the early dairy farmers who settled on its flanks.

Haystack mountain, near the tiny railroad settlement of Niwot, and between the infamous city of Boulder and the farming community of Longmont, in Boulder County, is not known for its majestic heights like its more famous 14 thousand-foot neighbors. Nor is it famous because it catches the eye with its glistening ice fields, or forested slopes teaming with Colorado’s abundant wildlife. No, Haystack mountain enjoys prominence only because it has stood for over a million years on the banks of a small creek, and at the confluence of a historic meeting of two vastly different cultures, the Native American Arapaho tribe who called it home for a millennium and Colorado’s early gold and silver miners who followed Left Hand Creek into the mountains near Boulder to discover their fortune.

Rising abruptly out of the prairie, in the center of the Left Hand Creek watershed, Haystack Mountain can only boast a three-hundred-foot summit! Covered with prairie grass, and arid landscape vegetation, this tiny pinnacle is not even shaded by a single tree! Haystack mountain can claim no ice field or glacier, either. No sparkling water falls from its mounded summit and no fantastic rock formations greet the wayward explorer. Haystack mountain cannot even lay claim to abundant wildlife. It is frequented only by a lone prairie dog, maybe an elusive rattlesnake, some field mice and a hungry coyote. At times, people have spotted a stray deer, bear or even a lonely elk, none of which would call Haystack Mt. home. Birds of prey however, find it a perfect visual vantage point and often can be seen circling its summit in search of an evening meal. And finally, if one did happen upon its rather steep slopes they would be in no danger of falling into a cauldron of hot volcanic lava, or ever being brushed with the steam of a long dormant vent, because Haystack mountain is many things, but it is not a volcano, and it never has been, in spite of the rumors often spread by earlier settlers along Left Hand Creek. “Most of the early settlers assumed it was a volcano and didn’t want to settle anywhere near it,” said Suzanne Webel, a Boulder County geologist.

So how did this little mound of rock and shale and sand appear on the prairie, a focal point for the area, and the centerpiece of the Left Hand Creek watershed. Like every mountain Haystack’s story began long, long ago…

What is now Haystack Mountain, was once part of Table Mountain, said Webel. Table Mountain is the plateau just northwest of Haystack Mountain, identifiable by the two large dish antennas on its northern flank.

About 70 million years ago, during the late Cretaceous period when dinosaurs still roamed in what is now Colorado, an extensive shallow sea left muddy deposits that became poorly consolidated into the thick layer of Pierre Shale that underlies much of the area. Before streams went to work eroding these deposits, they used to be thicker and more continuous than they are today. This soft rock forms the bulk of Haystack Mountain.

About 1.8 million years ago, long after the uplift of the present-day Rocky Mountains, during the Ice Age or Pleistocene period, there was a major outpouring of coarse sediments eastward from the mountains. These sediments contain a hodge-podge of rocks of all types, from whatever source happened to be uphill: granite, gneiss, quartzite, limestone, and sandstone. Dinosaurs had given way to woolly mammoths and saber-toothed tigers. These variably consolidated deposits of gravels and conglomerates are called the Rocky Flats Alluvium, which rests on the much older Pierre shale of the earlier period.

The Rocky Flats Alluvium became a hardened layer on top of softer rock. Streams then began cutting their way through the hard layer and into the softer deposits underneath, leaving behind tables, or mesas, such as those you see along the Front Range. Left Hand Creek, and its tributary James Creek, drain the local mountains in roughly an easterly direction (oddly oblique to major, mapped faults) at a latitude corresponding to Niwot or Nebo Road. When it reaches the valley west of the Front Range (Olde Stage Road corridor), the creek diverts north and exits the mountains just west of Plateau Road (after merging with Geer Canyon Creek). It is believed by some geologists that at one time the major drainage did not divert, but rather emptied into plains just north of the old Ball Aerospace facility.

At some point during the past 1.8 million years, these rivers and streams began to cut away the southeast portion of Table Mountain, opening a wider and wider gap between the bulk of the plateau and the much smaller Haystack Mountain. There’s even a saddle between the two mountains, Webel said. Haystack Mountain has held its shape thanks to a remnant of the hard layer at the top, called a caprock. Believe it or not, the very top of Haystack Mountain is all that is left of a vast sheet of Rocky Flats Alluvium (sorry, folks, this little pinnacle is not a volcano!). This conglomerate layer may be the source of the cobbles and boulders scattered over the lower slopes of Haystack Mountain. The similarity of gravels on Table Mountain and Haystack Mountain, and the conformity of their summits give support to the idea of a widespread conglomerate layer of which has protected the summits from erosion for thousands upon thousands of years. Finally, what is truly amazing is that a once roaring torrent of water, crashing out of the mountains to the west, diverted from its ancient course and has become the shorter, deeper valley of the now quiet stream known as Left Hand Creek, which now lies to the south of Haystack mountain, after having cut its path between two mountains, bringing to life what we know today as our beloved Haystack Mountain!

Haystack mountain may not be a volcano, but rather is a prominent geological feature that not only has a remarkable ancient history, but more recently a profoundly important modern history. As mentioned Haystack mountain lies at the crossroads of two vastly different cultures in human history. From time immemorial, this prominent feature served as a perfect observatory for the ancient peoples crossing the plains in the shadow of the Rocky Mountains. In more recent times, legend has it that the now famous Arapaho Indian, chief Niwot spent the winters in its shadow and today there are remnants of these proud people found at the base of Haystack in the form of ancient teepee rings and fire pits. In her book, Chief Left Hand, (Niwot in the Arapaho language) by Margaret Coel, it is clear that the Arapaho Indians were the first modern culture that made their home along the banks of Left Hand Creek, using Haystack Mountain as the logical high point on the plains to look out for any marauding enemies or wayward visitors. One wonders if they stood upon its summit and saw the approach of the first white settlers who arrived in the area having followed the South Platte River from Nebraska, to the Saint Vrain, and finally the watershed of Left Hand Creek to arrive at this unusual promontory on the plains.

These settlers, the Affolter family, built one of the early buildings in Boulder County. As stated in the notes of a Mr. Tom Kiteley at Old Mill park in Longmont, where this iconic cabin now resides, “The Affolter Cabin was built in 1860 near Haystack Mountain on Left-Hand Creek, west of Longmont”. Haystack is a weird, pointy hill west of town; I had a friend ride a bicycle down the hill once… idiot! He was all right until he hit the barbed wire at the bottom. There should have been good land in that area, though the Swedes settled out there and Garrison Keillor suggests they had great affinity for the rocky soil of their home lands. John Affolter was one of the earliest settlers in the St. Vrain Valley and the cabin’s extensive lifetime can be seen in the age of the notches and layout of the construction of the cabin. The original cabin craftsmanship can still be detected. Statehood waited nearly another decade and was probably won using less-than-ethical strategies that ignored the sinking population after the first gold rush flash. Horace Greeley had yet to be impressed by a specially salted mine. The cabin was donated to the Longmont Historical Society by the Dodd family who eventually farmed most of the land around Haystack, and relocated the cabin to the park.

In her book Margaret Coel also mentions a first meeting in this same cabin, between Chief Left Hand, or Chief Niwot and the Affolters. Others too give witness to this infamous interaction. “While Affolter was living in the house in the mid-1860s, the Arapaho Chief Niwot visited and camped around the cabin The property was a favorite wintering spot for the Arapaho Indians who found a good supply of game and drinking water in the vicinity. Stone rings about 20 feet in diameter are still visible some 200 yards southwest of the cabin. These stones were used to hold down the edges of the tepees. Between 1867 and 1876 the cabin was used periodically as the headquarters of the F.V. Hayden Survey which made geological maps and reports of the Rocky Mountains (Darby, 1970). (information gathered from “the Dodd Property, a historical study by the University of Colorado”)

Thus, the two cultures came together for a short period of time, before the great Indian chief met his untimely death at the banks of the notorious Sand Creek, in the Sand Creek massacre. How different history may have looked had he only stayed home in his camp at the foot of Haystack Mountain!

However, what remains of the white settlers is clearly evident today in the ever-changing watershed of Left Hand Creek. Now Haystack Mountain golf course graces its base, and thousands of people have found residence in its shadow.

How long will Haystack Mountain survive? Like Table Mountain, Haystack Mountain is slowly eroding, because of rain, snow and wind. After first being hesitant to narrow it down to anything more specific than “it could be a hundred thousand years, it could be a million,” Webel provides a more specific number.

Regionally the long-term erosion rate seems to have averaged between 0.1 mm/year (and) 0.9 mm/year … Anyway, if we try an average of 0.5 mm/year, and if we assume that the tip of Haystack Mountain is 300 feet above the valley, and convert 300 feet to millimeters, it’s 91,440 mm high. That means Haystack Mountain would disappear completely in 182,880 years. Exactly.

That is of course unless curious hikers slip past the watchful eyes of the current owners, the Ebel family, and hike its summit. Then the erosion they cause could rapidly bring about the untimely demise of our proud little mountain along the watershed of Left Hand Creek.

As Johnny St. Vrain shared in his article on the origins of Haystack mountain, upon which much of this information relied, “Ha! … Nothing in geology is ever that clear-cut, of course, but we can still engage in fun little speculations.”

Maybe it would have been better if Haystack Mountain was a volcano…its future would be much more certain! If this tiny mountain was still growing, curiosity seekers might stay off its summit and its slow demise would stop. In fact, had it been a volcano, Haystack Mountain would have had a glorious future as it continued to grow, and taken its place among the giants of Colorado! But it is not a volcano. It is a priceless monument, a witness to history and a testimony to the power of water, wind and rain along the watershed of Left Hand Creek.

Submitted by Gregory K. Ames

Landowner and LWOG Board Member