The edge of the hill country
From a distance, eh, whut
But you’ll KNOW you’ve climbed --
Proved you have the stuff
And the views around
Take remaining breath away
Generations aren’t wrong --
The Mount’s worth the stray!
INTRO:
Mt. Bonnell, summiting at 775 ft above sea level is said to be the highest point in Austin – and the incredible views certainly support that theory. However, ‘define Austin.’ What with urban creep and a general attribution of “Austin” to the greater “Austin Metro” Mt. Bonnell must look ‘up’ to parts of the Jollyville Plateau (just over THERE), which tops out at 1100 feet – oh well!
Sam Houston once climbed the peak with Judge R. M. Williamson, a former Texas Ranger. The big general is supposed to have slapped Williamson on the back and proclaimed: “Upon my soul, Williamson, this must be the very spot where Satan took our Savior to show and tempt him with the riches and beauties of this world!” [1]
THE SETTING:
775 feet above sea level sounds “a fer piece up thar,” here on the edge of the Blackland Prairie. Of course, ambiently, you’re only about 200 feet above Lake Austin. Though that IS a fair piece of altitudinal change – 190 feet of it up the 100 steps of the staircase from the parking area.
A favorite destination for locals and tourists alike, excursionists have been probably summiting Mt. Bonnell for millennia. Documented visits go back to the mid 1800s.
The Austin Daily Bulletin reported on Dec. 13, 1841 “A large party of ladies and gentlemen incited by the fineness of the weather and making use of the vacant time during the temporary adjournment of Congress made an excursion on Saturday morning to Mount Bonnell and the country adjacent.” The newspaper editor notes that his “editorial duties” had “precluded [him] from the pleasure of participation.” But it does seem everyone else in town made the trip: “The party consisted of 40 gentlemen and 10 ladies, who returned to town in formal array, the armed portion of the cavalcade in advance.” The 40 gentlemen included Republic of Texas Vice President Edward Burleson, along with the French ambassador, members of the republic’s Congress, “professional men and plain citizens, many of them temporary visitants…who will certainly go home with a vivid recollection of the sunny and variegated beauty of the scenery around Austin and the salubrutity of its atmosphere.” [2]
Armed escorts? Yes. At that time Austin lay on the farthest outpost of settlement on the Texas frontier – and ‘sovereignity’ of Texas was still under dispute. Especially between the expatriated US gringos and the local First Nation tribes.
“Despite the threat of Indians, the editor of the Bulletin obviously hated that he had missed the trip. ‘We wanted to scent the pure air of the mountains,’ he waxed on, clearly needing some time out of the office, ‘to encircle with the heart’s vision the beauty of the scene, to look again over the dark blue peaks of which the memory of our boyhood still has some reminisces, and upon the river with its gentle current running far beneath, and the wood upon its borders, for we think it one of the pleasantest sights in nature to look down upon running water and the varied verdance of a forest.’” His yearning regret of this missing this outing, “merry as a marriage bell,” concludes: “We count such a day’s enjoyment, worth a year of common life, and reiterate our regret at not having been there.” [3]
No armed escorts required these days, but you still get a mild workout with your visit. The aforementioned 100 stone steps with their 190 or so feet of elevation gain let you know you’ve made the climb. But take your time and remember the scenery is worth every huff and puff. Once you reach the top, you’ll find a picturesque pavilion and sweeping views, particularly to the west into the Hill Country. Downtown Austin can be seen to the southeast. Trails lead north and south along the summit, affording additional vantages (and a chance to get away from the sometimes maddening crowds congregating around the pavilion).
THE GEOLOGY:
A mere 300 million years ago (give or take), this was the seashore. Eons of erosion and deposition built up, causing a shear right along here at the Balcones (for “balcony”) Escarpment in the Tertiary period – about 65 million years ago. Basically everything to the east ‘slumped,’ but here at the seam rocks were faulted and crumpled. Water, such as the Colorado River below, did its work over the centuries along the various fault and fracture lines, leaving the steep valleys you see around you. The Balcones Escarpment has long gone quiet – the last earthquake activity was during the Miocene, about 15 million years ago, likely triggered by additional subsidence of the coastal plain under the weight of all the river and gulf sedimentary deposits.
Mt. Bonnell perches on the Balcones Fault Zone “divide.” Upstream is the higher (uplifted) section of the Balcones and the Hill Country – a.k.a. the Edwards Plateau. Downstream extends out into the Blackland Prairie – essentially flat all the way to the Gulf. The rock under your feet was deposited as limy muds and oozes with some occasional sands on the shallow sea bottom during a period roughly 180 to 80 million years ago. [4]
Mt. Bonnell itself is comprised of Glen Rose limestones from the lower Cretaceous period (late Upper Aptian into the Lower Albian), meaning these rocks are about 115-105 million years old. Glen Rose topography (famous for dinosaur tracks, though you won’t find any up here to my knowledge) tends to be terraced, alternating hard and soft layers of limestone. “The east slope of the summit of Mount Bonnell …is a familiar example of the terraced Glen Rose slopes, the different benches succeeding one another like the treads of an ordinary stairway.”[5] While we are familiar with water shaping our landscape, here you can also see the effects of wind, which blows away the powdery material of the softer Glen Rose layers, undermining the hard, rocky layers until they become projecting shelves, which then collapse under their own weight. The bluffs of Mount Bonnell are largely of this nature. Interestingly, “the very steep and in places impassable bluffs of the western side of Mount Bonnell have been formed from the same beds which on the other side of the mountain weather into terraced slopes. It is necessary only to follow the terraced beds of the eastern face of this mountain around to the west side to observe the change from the bench and terrace to the bluff character.” [6]
Note that the bedding here is essentially horizontal. To the east, on the ‘graben’ (or dropped) side of the Balcones Fault Zone, you’ll find tilted bedding and more fracturing, until it’s completely covered by the deep soils of the prairie.
You can also expect to find some marine fossils in the area – though Mt Bonnell itself is pretty picked over. Most commonly found are varieties of oysters (and the most common of those are the Texigraphea oysters, well over 100 million years old), as well as a fair number of bivalves (clams), depending on where you’re looking. Kinda fun to beach comb in the heart of Texas!
THE NAME:
There are two candidates for the Mt Bonnell moniker. Most popular is the attribution to Texas newspaperman George W. Bonnell, who published “The Texas Sentinel” and was prominent in early Texas and Travis County (Austin) affairs. Equally probable, however, is that Albert Sidney Johnston may have named Mount Bonnell for his friend and fellow West Point graduate Joseph Bonnell, a Captain and Aide de Camp to General Houston in the Texas War for Independence, and a recognized hero of the Texas Revolution. Unfortunately there is no ‘smoking gun’ documentation for either namesake.
More “romantically,” local legend claims Mount Bonnell was once called Antoinette's Leap, after a young woman who leapt to her death to escape the Native American raiding party that killed her fiancé.
THE PARK:
The setting for Mt. Bonnell is officially Covert Park – so named not because lovers sneak up there for a tryst, but, rather to honor Frank M. Covert Sr., who donated the land.
A wonderful carved limestone monument at the summit (familiar in form and history to those doing the spectacular multi-puzzle of GC2B034 Necropolis of Britannia Manor III by LordBritish) reminds us of that. Covert Sr. donated this tract to Travis County in 1938. The City of Austin acquired the property in the early ‘70s and transformed it into the Covert Park you see today.
Enjoy the view! Stay for the sunset – it is spectacular from here. But, mind, the park is closed from 10pm-6am.
PARKING COORDS:
N 30 19' 16.12"
W 097 46' 22.33"
FOOTNOTES & FURTHER READING:
[1] Mount Bonnell Covert Park Austin, Texas by Mike Cox; TexasEscapes.com (
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[2] Ibid
[3] Ibid
[4] Roadside Geology of Texas; Robert A. Sheldon; Mountain Press Publishing Co; 2nd printing 1982
[5] Glen Rose Formation from “Geography and geology of the Black and Grand prairies, Texas, with detailed descriptions of the Cretaceous formations and special reference to artesian waters Publication 4171875“ (
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[6] Ibid
Austin Explorer “Mount Bonnell” (
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Austin Parks Foundation “Mount Bonnell” (
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Austin Park Profiles “Mount Bonnell” (
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Guidebook to the Geology of Travis County Field Trip No.2 : Balcones Fault Zone (
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Guidebook to the Geology of Travis County Chapter 5: Collecting Localities for Fossils in Austin (
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Texas State Historical Association “Balcones Escarpment” (
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Quick Fossil Identification link at Bulk Fossils By PaleoScene www.paleo.cc (
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Wikipedia article “Mt Bonnell” (
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