Students observe the roadcut at Skimmerhorn St. and S. Overland Trail, Smokey Hill Shale Member of the Niobrara Formation, Upper Cretaceous. This is looking south.

RMHS students Matt Beltcher and Nathan Cano (l to r) take the dip of the Smoky Hill Shale. Students learned to use a Brunton Compass on the field trip as well as observe a variety of rock outcrops. This is looking southeast.

 Links to : Field Trip Stop 1 - Field Trip Map 1 and 2

Students scour the ground for fossilized Inoceramus (a mollusk) and Pseudoperna Congesta (similar to an oyster) in the Fort Hays Limestone Member of the Niobrara. This is looking south from the Fort Hays Limestone. Behind them is the valley formed by the Carlile Shale, Greenhorn Limestone, Graneros Shale and Mowry Shale. Beyond the valley the Dakota Formation rises above the Great Plains and the Rocky Mountains loom to the right (west).

A student holds a piece of Fort Hays Limestone with a piece of Inoceramus.

Inoceramus Example

 Links to : Field Trip Stop 2 - Field Trip Map 1 and 2

The top of the Dakota Group, South Platte Formation on the south side of the Spring Canyon Dam. This outcrop is at the parking area for Stop 3 looking north.

The South Platte Member is popular for bouldering. This is on the other side of the parking area for Stop 3 looking east.

 Links to : Field Trip Stop 3 - Field Trip Map 3 and 4

The Plainview Sandstone Member of the Dakota Group sits atop an unconformity with the Lytle Formation (red line roughly divides them). The Lytle in turn lies at an unconformity with the Morrison Formation (green line roughly divides them). This point is at the junction of W. County Rd 38E and S. County Rd. 23 as it comes south across the Spring Canyon Dam. The top of the Dakota forms the hogback on the left of the picture. The view is looking south with Spring Canyon Dam behind the view. This is a mosaic from 2 different images.

Here the Morrison Formation shows its characteristic coloring of green, red, and white weathered claystone and siltstone. This is southwest of the above image, looking roughly southwest.

A thin green layer of the Morrison Formation lies just above the head of the hammer. The rock crumbles very easily.

 Links to : Field Trip Stop 4 - Field Trip Map 3 and 4

A view toward the northeast from "The Perch" on the west side of Horsetooth reservoir and on the top of the road as it crosses the Lyons Sandstone (Stop 5). In the foreground is the Lyons Formation on the north side of the Buckhorn Creek Fault. The red colored foreground is the Owl Canyon Formation below the Lyons. Horsetooth Reservoir is at its maximum elevation of 5430 feet above sea level, and rests on top of the Lykins Formation. The east (far) side of Horsetooth on the right is capped by the Plainview/Lytle Formation while the slop is Morrison and the small red outcrops are the Sundance and Jelm Formations. Spring Canyon Dam can be seen at the top of the water in view. Downtown Fort Collins is directly above the dam in the distance.

The Lyons Snadstone is very well cemented and is used extensively as a building material. Many of the building on the Colorado State University campus and in Fort Collins were made from Lyons Sandstone quarryed in the town of Stout, CO, at the south end of Horsetooth reservoir. This view is looking west across from "The Perch" - Stop 5.

 Links to : Field Trip Stop 5 - Field Trip Map 5 - Field Trip Map 5, 6, and 7

This is a picture from the trail above Stop 6 looking back along the road as it follows the Buckhorn Creek Fault. The view is to the southeast and follows the fault as it snakes between the Boulder Creek Granodiorite of Milner Mtn on the right and the Quartofeldspathic Mica Schist of Horsetooth Mtn Park on the left. The Green line marks the strike of the fault as it heads east, across Inlet Bay, and up the road once again east of Inlet Bay to Stop 5.

 Links to : Field Trip Stop 6 - Field Trip Map 5, 6, and 7

Pegmatite Dike in Quartzofeldspathic Mica Schist at Stop 7. The pegmatite stands out as more resistant rock and is better exposed here at this road cut. The pemntatie is made up of quartz, feldspar, muscovite, and tourmaline.

Just to the right of the hammer is a brown xenolith of the quartzofeldspathic mica schist which shows foliation consistant with the surrounding country rock. Black tourmaline crystals can be seen above the hammer about a hammer length.

 Links to : Field Trip Stop 7 - Field Trip Map 5, 6, and 7

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