Guidebook—Geology of South-central Kansas
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Stop 2 to Stop 3
From the Micro-Lite Quarry, we backtrack about 0.75 mile to the east-west gravel road, where we turn right (west) for 1 mile, and then left (south) for another mile, passing a quarry in the Stanton Limestone on the south flank of the Silver City Dome. At the T-intersection, we turn right (west) for 1.5 miles until we come to Middletown. The hills along this stretch mark the southwest rim of the Silver City Dome. At Middletown, we turn left (south) again for 1 mile. At the T-intersection, we turn right (west) and travel 2 miles to the crossroads, where we turn left (south) and curve to the right (west), crossing the Verdigris River. The elevation of the river is about 845 feet--the lowest point on the trip. We'll continue west for about 1.5 miles to the junction with a blacktop road, where we turn right (north) and travel 3 miles to the junction with Kansas Highway 105.
On K-105 we continue north and eventually west for about 5.3 miles, passing along the east side of Toronto Lake. On the east edge of the town of Toronto, we turn left (south) on Point Road and continue for a little less than 2 miles to the Toronto Point area of Toronto Lake State Park (Stop 3).
Stop 3—Toronto Lake
Toronto Lake was completed in 1960 and occupies approximately 2,800 acres. The park encompasses an additional 1,075 acres and offers visitors recreational activities such as swimming, fishing, water skiing, camping, hiking, picnicking, and wildlife observation.
Picnic grounds at Toronto Lake, Woodson County.
Located in the gently rolling terrain of the Verdigris River valley, Toronto Lake marks the northernmost reaches of the Chautauqua Hills physiographic region, a region of sandstone hills formed on thick sandstones in the Lawrence and Stranger Formations. These sandstones were deposited in deep, alluvial valleys during the Pennsylvanian Period, at a time when the area was above sea level. A patchwork of oak woodlands and tallgrass prairie cover the hills in this region; as a result, they are sometimes known as the Cross Timbers, a vegetative complex that extends southward into Oklahoma and central Texas.
This stop gives us a chance to see one of the sandstones that characterizes this region, the Ireland Sandstone Member of the Lawrence Formation. The Ireland Sandstone was deposited in an ancient river valley that existed in eastern Kansas during the Pennsylvanian Period. At that time this part of Kansas was above sea level, and the seashore was southwest of here. This stream flowed in a south-southwest direction and deposited sand in a broad deep valley several miles in width that can be traced north-northeastward into the Leavenworth area. This stream valley was filled with sand up to at least 160 feet in depth, which has since been cemented into sandstone.
Outcrop of Ireland Sandstone at Toronto Lake, along Kansas Highway 105.
Where this sandstone is at or close to the surface, rain and runoff have soaked into the pores between the sand grains and created a freshwater aquifer that supplies water to farms and some small towns in its vicinity. This sandstone contains structures such as ripple marks and crossbedding, which are indicative of deposition by running water. Usually limestone and shale have horizontal bedding planes, but high-energy streams create dunelike structures on their streambeds. Sandstones deposited under these conditions have bedding planes in a confusing array of angles and directions.
Stop 3 to Stop 4
From Toronto Lake, we'll backtrack north to K-105 and turn left (west), following the highway west and north through Toronto, until we meet U.S. Highway 54. We take Highway 54 west for about 7 milesto the gravel road on the east side of the small town of Neal. We turn left on the gravel road and follow it south and east in a stairstep fashion to the roadcut in the prominent hill just north of the road. This is Round Mound (Stop 4).
This guidebook is also available in print form as Kansas Geological Survey, Open-file Report 2001-41, from KGS Publications Sales office, 785-864-3965.
Unless noted otherwise, illustrations by Jennifer Sims, Kansas Geological Survey; photographs by John Charlton, Kansas Geological Survey. Text by Jim McCauley, Liz Brosius, Rex Buchanan, and Bob Sawin, Kansas Geological Survey.
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