Toronto’s Union Station is a National Historic site and is Canada’s finest example of a classical beaux-arts railway station. Construction began in 1914 at a time when there was a materials shortage due to World War 1 . The station officially opened in 1927 and has endured more than 92 years of wear and tear.
The city of Toronto purchased Union Station in 2000 and moved forward with plans for a multi year revitalization of the station that concluded in July 2021. The newly restored rail hub serves over 300,000 visitors each day.
The materials used in the construction of Union Station include Zumbro limestone blocks from Missouri for the interior walls in the great hall and a composite of crushed Zumbro, also known as artificial Zumbro, which was used to cast the ornamental shapes which simulate carvings, an easier task than carving directly into the stone blocks. The exterior walls of the station are Indiana and Queenston limestone and the interior floor are made of Tennessee marble.
As part of the restoration and revitalization project, a big challenge included restoring the stone and replacing cracked or broken blocks. Zumbro quarry is now closed and no more stone was available, so matching limestone blocks were used. Another issue noted by engineers was that the artificial Zumbro ages differently from the real Zumbro stone, and the two stones had a distinctly different visual perspective from when the building was originally erected, so careful cleaning and restoration was needed.
Fossil impressions
Fossil impressions are imprints or indented marks showing the remains of plants or animals from long ago. These plant and animal impressions were left in mud, silt or sand. Over time and exposure, the plant or animal remains decay and erode away, leaving just the impression, or just a cavity with a distinct shape of the remains. The empty space in the shape of the organism is referred to as a cast. Often these casts show the ridges of a shell or exoskeleton of the animal.
Fossil impressions are found preserved in sedimentary rock, normally clay and shale, however volcanic ash may sometimes preserve plant fossils as well.
Fossilized impression of a Cycad leaf found in California
Fossilized impression of a shell, possibly a Whelk shell, that has eroded, leaving behind an impression..
Trace Fossils
Also known as ichnofossils, trace fossils show a geological record of activities and behaviours of past life. Trace fossils include
- Track and trails ( footprints)
- Burrows and bores ( worm holes)
- Gastroliths ( stomach stones or gizzard stones)
- Coprolites ( fossilized feces)
Trace fossils may consist of impressions made on or in the substrate by an organism. For example, burrows, borings (bioerosion), urolites (erosion caused by evacuation of liquid wastes), footprints and feeding marks, and root cavities may all be trace fossils.
The term in its broadest sense also includes the remains of other organic material produced by an organism including coprolites (fossilized droppings) and chemical markers (sedimentological structures produced by biological means. However, most sedimentary structures like those produced by empty shells rolling along the sea floor are not produced through the behaviour of an organism and thus are not considered trace fossils.
Body Fossils
Body fossils are the remains of plants, animals or in some cases bacteria that has fossilized in a large colony called stromatolites.
Body fossils include teeth, bones, skin, eggs, leaves, wood and even bark. In Ontario’s sedimentary limestone, it is common to spot fossilized shells and crinoids in limestone blocks.
Earthcache Details
The posted coordinates are just outside of the eastern main entrance to Union Station located on Front Street. (See Photo below)
Enter through the main doors into a vestibule just outside of the main gallery. On your immediate left you will see two doors leading to Stair CB-007
To answer the following questions, you will need to look at the Zumbro limestone blocks on either side of the entrance to the stairwell.
Logging Requirements
- This earthcache is available 5:30AM-12:45AM when Union Station is open.
- You will need to make observations of the Zumbro blocks on either side of the doorway to the stairwell.
- Send your answers within 4 days of your visit and add your photos to your log.
- Group answers for questions 1 and 2 are allowed. For questions 3 and 4, each cachers log will need to add the mandatory photos as proof of their visit.
Use the following photo to answer the following questions
Questions
1. Look at the block identified in the photo as Block A. There is a large fossil in this block that is running horizontally on the block.
a) What is the width and length of this fossil?
b) Do you believe this is a body fossil or an impression fossil?
2. What is the name of the type of limestone blocks used for the interior walls and in the great hall of Union Station from the write up? Where was this stone quarried?
3. Find an example of a fossil impression, either a leaf or body fossil. If you are unsure, look at the images in the gallery which are labeled. MANDATORY: Take a photo showing you pointing to a fossil impression and post it with your found Log
4. Find a second fossil, either a body fossil or a burrow/bore fossil. MANDATORY: Take a photo and identify which one you found and post it in your found log. There are examples of both types in the Zumbro limestone blocks in the vestibule and surrounding the entrance to the stairwell.
