This earthcache is located outside of the exclusive Terminal City Club, 837 W. Hastings St. Only members are allowed inside. So unless you are among the lucky few, this cache has to be done from the plaza beside the club. The easiest way to access this cache, because the coordinates are bouncy with all those tall buildings, is to go past the front door, walk west down West Hastings until the end of the building, turn right down the plaza beside the wall, walking by the shops. At the end there is an exit door to the hotel/club at right angles to the wall. The cache is at the second slab from the exit door. There are four stories of mottled limestone slabs on the building.
The building panels which veneer the front of the building at sidewalk level is fossiliferous limestone. It is a beige coloured, large scale cross bedded grainstone, a type of limestone made of sand sized fragments of shells. But the really interesting thing about this limestone is it is made entirely of shells made of calcite and was imported from Bruni Oggi quarry, a limestone quarry near Carrera Italy. (Michaelango’s David marble was quarried near here, a metamorphic rock which comes from limestone).
This limestone/dolomite was imported from near Winnipeg and is called Tyndall Stone which has been quarried since 1832.
On the the entire west side of the building facing the plaza at the co-ordinates, is tan and grey, burrow mottled (fossilized mottles which were probably made be shrimp like creatures) limestone/dolomite with large fossils such as 15 cm diameter coral-like stromatoporiods (which are calcareous sea sponges common in the fossil record from the Ordovician through the Devonian.), 5-10 cm bivalves (clams, oysters), snails, and cephalopods (squid, octopus or nautilus). You can see a large (3in x2in) sea sponge fossil on the second panel at shoulder height from the back door. You can also see smaller clams.
For a more detailed description of Tyndall Stone see https://coord.info/GC12TPF and the drawing below is a representation of how the mottles are formed.
A typical fossil, commonly called a sunflower coral, on the terminal city club looks like this. There is some controversy whether it is a coral or a sea sponge.
What is a dolomite you ask? Well, limestone is a calcium carbonate rock whereas dolomite is made of calcium magnesium carbonate. Sand, clay and silt are commonly found in limestone as impurities but not commonly in dolomite. Pure calcite limestone is usually more expensive than dolomite.
Your task is to let me know by email or messenger the following:
1. Based on the size of the mottles, estimate the size of the creature that did the burrowing.
2, What would this rock become if it became metamorphic?
3. Post a picture of something personal such as you, your GPS or phone against a fossil or mottle you found in the limestone, or beside the large fossil shown in the photo above.
Congratulations to Moxyscott for the FTF about 10 minutes after it was published.