In Wisconsin, United States
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Welcome to Grandad Bluff, overlooking the city of La Crosse. You can drive to it via Bliss Rd (Main St. turns into this at Losey Blvd.) and turn right at the first intersection to get to the bluff overlook.
La Crosse is in the area of Wisconsin known as the Driftless area. This is because the glaciers never game this far into Wisconsin and the area was left untouched. Lake Michigan and Lake Superior deflected the glaciers to the east and west of this area, and its’ elevation helped it to avoid being covered. We get the deep, wide valley the Mississippi River is in from the glaciers melting. The melt water would come in huge amounts at a time and carve its way through the sandstone and undercut the bluffs that we see today.
The bluffs (or mesas) in La Crosse are Prairie du Chien dolomite that caps Cambrian sandstone from about 440 million years ago. The dolomite is a harder rock that caps off the bluffs and is from Ordovician time. It commonly has oolite and chert nodules in it, but has very few fossils, just stromatolites (algae fossils) and animal burrows. At this time, the sea that covered the area was very salty and wasn’t very hospitable to living creatures.
The sandstone is all from the Cambrian time. The top layer underneath the dolomite is Jordan sandstone, which is made from quartz sand. Under this, we have (in order) the St. Lawrence Formation, the Tunnel City Formation, the Wonowoc Formation and the Eau Claire Formation. The city of La Crosse is on the Eau Claire Formation. These sandstones are poorly cemented, so do not make cliffs, but slopes. The sandstones were created differently, and one can tell how they were made by looking at the crossbedding, which is the lines that cross the sandstone. The ripples are larger when they are created by water (as opposed to wind) and are symmetrical if created by waves and asymmetrical when created by currents. In the sandstone, there are fossils of marine life, as Wisconsin was a tropical sea at the time the sandstones were being created. The youngest sandstones (towards the top) had few fossils, but as one moved down the bluff, there will be more fossils. In the finer, shaly sediments, there is more animal diversity. Towards the bottom of the bluffs (the oldest area) the sandstone is coarse and pebbly – the sea was advancing and had tidal currents.
Grandad Bluff and what is now known as Hixon Forest was saved from quarrying and logging in 1909 by Joseph and Ellen J. Hixon. It was donated in 1912 to the City of La Crosse and is a park that many people have used since its beginning.
In order to get this cache, you must do these things as soon as you log the cache, or it may be deleted. Please email the answers to the cache owner.
1. What is the elevation of Grandad Bluff?
2. What happened here in 1850 (sign by parking lot)?
3. What is the farthest object you can see at the overlook? How far away do you think it is?
4. Take a picture of you and your GPSr (or if alone, your GPSr) at the overlook.(optional)
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Last Updated: on 10/27/2014 4:57:19 AM Pacific Daylight Time (11:57 AM GMT)
Coordinates are in the WGS84 datum