Back into Time

At this present day the altitude high up on the Molas Pass where you now stand is 10.893ft (3320m) with stunning views ....... but it wasn't always like this!
Animas Glacier
During the Pleistocene (2.6 million to 11.700 years ago) this location looked totally different.
The valley was occupied by the largest glacier in the range. The Animas Glacier extended 50 miles down the valley to Animas City and Durango.
It was fed by over 75 catchment basins and the ice was as much as 2000 feet thick. The valley has been eroded by alternating glacial and fluvial action aided by mass-wasting which is very common in some areas.

From Seafloor to Summit
Going further into the past at this location, 75 million years ago you would have stood under the sea level.
Imagine a vast shallow ocean covering much of what is now Southwest Colorado. The shoreline constantly changed as the ocean fluctuated in size.
Prehistoric rivers deposit silt and sand into the ocean and small creatures flourished. Over time, this material compressed into thick layers of sedimentary rock ... siltstone, sandstone and fossil-bearing limestone.
What once lived in the ocean can be found just a step away from were you are now standing at 10.900ft.
Marine fossils - crinoids, gastropods and brachiopods are the evidence in the sedimentary layers forming the "benches" of the Hermosa Formation at Molas Pass.
Marine Fossils
CRINOIDS
Because many crinoids resemble flowers, with their cluster of waving arms atop a long stem, they are sometimes called sea lilies. But crinoids are not plants. Like their relatives--starfishes, sea urchins, sea cucumbers, and brittle stars--crinoids are echinoderms, animals with rough, spiny surfaces and a special kind of radial symmetry based on five or multiples of five.
In the ancient seas these crinoids were so plentiful they formed "gardens" on the sea floor. Crinoids flourished during the Paleozoic Era, carpeting the seafloor like a dense thicket of strange flowers, swaying this way and that with the ocean currents.

GASTROPODS
Gastropods are the most diverse and abundant type of mollusks. The marine shelled species include edible species such as abalone, conches, periwinkles, whelks, and numerous other sea snails that produce seashells that are coiled in the adult stage—though in some, the coiling may not be very visible, for example in cowries.
In a number of families of species, such as all the various limpets, the shell is coiled only in the larval stage, and is a simple conical structure after that. They come in all sizes from microscopic to large.
The earliest representatives of the group appeared in the Late Cambrian and by the Ordovician period the gastropods were a varied group present in a range of aquatic habitats.

BRACHIOPODS & PELECYPODS
Brachiopods and pelecypods belong to the large category of animals without backbones, the invertebrates. They have two shells or valves which house the creature inside and in many ways they resemble eachother.
The key difference between them is in their respective symmetries.
Pelecypods have a line of symmetry along their hinge line. This means that the top and bottom shells of the animal are mirror images of one another.
The two shells of the brachiopod are not alike. The animal living inside the brachiopod shell is very much different compared to the one living in the pelecypod shell.
They come in a variety of shapes and sizes and have a fossil record stretching back to the start of the Cambrian Period.

Questions
To get credit for finding this earthcache:
Please do NOT post answers in your logs!
Please e-mail me "GC650KZ - Back into Time" and the answers to the following questions. Add the names of other cachers in your group.
Unfortunately if I don't receive answers within seven days, logs will be deleted.

1. How can you see the glacier left his mark of erosion on the landscape when you look around (be specific)?

2. What is the cause we can now find marine fossils at the Molas Pass?

3. To answers the next questions I want you to be a student paleontologist.

I examined the rockwall myself and quickly I found some fossils.
The above picture has 3 markings were you can find marine fossil evidence (you won't need extra information besides the explanation of fossils on this EarthCache page). Feel free to investigate the wall further to find more fossils!
A. Describe what you see at mark A and based on your observation determine what kind of fossil this is.
B. Describe what you see at mark B and based on your observation determine what kind of fossil this is.
C. Describe what you see at mark C and based on your observation determine what kind of fossil this is.

4. Optional and not required for logging EarthCaches is posting a picture of yourself onsite, but no spoilers please (no close up from the fossils as this is part of the task).

Additional Waypoints

01650KZ - Stage 2
N 37° 44.254 W 107° 41.826

P1650KZ - Parking
N 37° 44.225 W 107° 41.845