I have heard many a person saying that they live in a city, and will never see any fossils, or that they cannot physically get to fossil sites in the outdoors as they are not able. Well, no need to worry, there is plenty to see in the city of Glasgow itself. This EarthCache is suitable for the disabled, those with strollers and children. It is meant to be interesting and educational. Please be respectful to others in the station.
This EarthCache takes you to the main entrance of the station. We are here to look at the cladding of the entrance way.The cladding is formed from limestone. Limestone is a sedimentary rock.
Sedimentary rocks are types of rock that are formed by the deposition and subsequent cementation of that material at the earth's surface and within bodies of water. Sedimentation is the collective name for processes that cause mineral and/or organic particles to settle in place. The particles that form a sedimentary rock by accumulating are called sediment. Before being deposited, the sediment was formed by weathering and erosion from the source area, and then transported to the place of deposition by water, or wind. Sedimentation may also occur as minerals precipitate from water solution or shells of aquatic creatures settle out of suspension.
Limestone is a sedimentary rock composed largely of the minerals calcite and aragonite, which are different crystal forms of calcium carbonate. Many,but not all limestones are composed of skeletal fragments of marine organisms such as coral, crinoids and molluscs.
There are plenty of EarthCaches which describe the subjects of limestone and weathering, we are
here to learn about Crinoids.
The fossils that we have here, are known as Crinoids. Crinoids lived in a tropical sea, and composed of a stem, and its 'arms' which it used to catch prey. What we can see here, are the remains of the stems. The stems are composed of a number of round ossicles, which join together to form the stems that we see. The ossicles were hollow, hence why they look like tubes when seen today. Some of the stems appear to have a spiky inner, that is because when cut through, they have a star aappearance.
Examples of crinoid stem and ossicles. The photos are my own.
This being an EarthCache, in order to log it, I ask that you answer the below questions. Please send them to me, and do not include them in your log. You can send them to me by using the message facility or email, both of which can be found by looking at my profile.
1. Please look along the whole of the cladding and find the longest crinoid stem. How long is it?
2. Please measure the diameter of this stem, and the width of the ossicles which form it.
3. Please describe the crinoid fossils, are they in an regular order, or are they a mismatch of stems?