Mount Bonnell
Mount Bonnell, commonly known as Covert Park, is a prominent peak along the Colorado River’s Lake Austin part in Austin, Texas. Since the 1850s, it has been a popular tourist attraction. The summit offers a panoramic view of Austin, Lake Austin, and the surrounding hills. It was designated a Recorded Texas Historic Landmark in 1969 and was added to the National Register of Historic Places in 2015.
Geography
Mount Bonnell may be found at 30.3210°N 97.7736°W. (WGS 84 datum). The mound is frequently referred to be Austin’s highest point, having a peak elevation of approximately 775 feet above mean sea level (AMSL). If Mount Bonnell ever possessed this distinction, it was only because the city borders did not include Mount Barker, which has an elevation of around 840 feet above mean sea level (AMSL). However, according to City of Austin records, the city annexed both Mt. Bonnell and Mt. Barker as part of the same tract “on or before” 1951; Mt. Bonnell joined the city boundaries with its higher neighbor, Mt. Barker. Many other sites in Austin are now higher than Mount Bonnell, but few publicly accessible spots have such a panoramic perspective of the city.
History
Mount Bonnell’s Indian Trail
The State Historical Survey Committee installed a historical marker at Mount Bonnell in 1969. The inscription on the monument reads:
This 775-foot-high limestone cliff was named after George W. Bonnell, who traveled to Texas with others in 1836 to fight for Texas freedom. President Sam Houston appointed him as commissioner of Indian affairs in the Republic of Texas. Moved to Austin in 1839 and established the “Texas Sentinel” there in 1840. Member of the Texan-Santa Fe expedition in 1841. Was arrested but released in time to join the Mier expedition in 1842. Near December 26, 1842, he was slain at a camp on the Rio Grande. W.A.A. “Bigfoot” Wallace, a frontiersman, killed an Indian he met face to face while traversing a precarious ledge 50 feet above the river in 1839. He too sought sanctuary in a Mount Bonnell cave to recover from “flux,” but he was gone for so long that his sweetheart fled. Mormons erected a mill on the Colorado River near Mount Bonnell in the mid-1800s. The water wrecked the mill, and the Mormons migrated west. Mount Bonnell was a popular spot for picnics and trips in the 1850s and 1860s. As it is now. Legend has it that an expedition to the location in the 1850s inspired the classic song “Wait for the Wagon and We’ll All Take a Ride”. Miss Hazel Keyes fell down a cable extended from the summit of Mount Bonnell to the south side of Lake McDonald below as a stunt in 1898.
When Bigfoot Wallace was asked why he picked the cave on Mount Bonnell as a refuge years later, he said, “Well, the cave was exactly on the ancient Indian road heading down to Austin… and furthermore, the cave was in the prime hunting field for bear in all this country.”
Mount Bonnell is said to have been named after early Texas newspaper publisher George W. Bonnell, who arrived to Texas in 1836. George W. Bonnell was the publisher of the local publication The Texas Sentinel and was active in early Texas and Travis County (Austin) politics following the War for Independence. Though sources have traditionally attributed the mountain’s name to George Bonnell, Albert Sidney Johnston may have called Mount Bonnell in present-day Austin after his buddy and fellow West Point graduate Joseph Bonnell, who served as a Captain in the Texas Army during the War for Independence. There is little evidence to support either origin of the name at the time.
According to legend, Mount Bonnell was named after Antoinette, a young woman who jumped to her death to avoid being kidnapped by Native Americans who had slain her fiancé.
Geology
Mt. Bonnell is part of the Balcones Fault Escarpment, which was identified by Bernardo de Miranda in 1756. The lower Cretaceous Glen Rose Formation limestone abuts the fault zone to the west but is buried 1000 feet to the east.
The Lower Cretaceous Trinity Group is followed by the Edwards Group and the Georgetown Formation in a geologic column. Following the Del Rio Clay, Buda Limestone, and Eagle Ford Group are Upper Cretaceous strata. The Hammett Formation, Cow Creek Formation, Hensel Formation, and Lower and Upper Glen Rose Formation are all part of the Trinity Group. The Middle Trinity Aquifer is confined (or aquitarded) by the Hammett and the lower half of the Upper Glen Rose. The Upper Glen Rose contains the Upper Trinity Aquifer, which appears to have intra-aquifer groundwater flow with the Edwards Aquifer due to similar water levels. The Kainier Formation and the Person Formation are two formations within the Edwards Group. The Edwards Aquifer is confined within the group by the Upper Cretaceous rock strata.
With a vertical throw of up to 600 feet, the Mount Bonnell fault is the most conspicuous normal fault within the Balcones Fault Zone. The Edwards Group was shifted downhill relative to the Glen Rose Formation in the Edwards Plateau during the Miocene, resulting in their juxtaposition.
Next Point of Interest: Zilker Botanical Garden