As you walk past this building, the facade may trigger a trypophobic person. But closer inspection shows some really cool features present here.

Logging Tasks

Send the answers to the following.

1. What type of stone is Portland Stone?
2. These holes, describe the most dominant shape. For an additional fossil lesson, Google "Aptyxiella Portlandica".
3. Using prior knowledge, can you deduce whether this rock formed in a merine environment or a terrestial environment?
4. What variety of Portland Stone was used here?
5. What are the types of fossils you can see here?
6. Attach an image of yourself at GZ to the log.

Portland Stone

Historically, Portland stone has been the most widely used of the Jurassic limestones of Britain. It is arguably the principal building stone of London, at least since the post-medieval period, and became popular in the 17th century following the demise of timber as the predominant construction material, particularly after the Great Fire of 1666. The source of this stone, the Isle of Portland, is a key part of the Dorset and East Devon Jurassic Coast.

Portland is a relatively pure limestone containing, on average, 95 per cent calcium carbonate. It is creamy white in colour, weathering to a duller greyish brown tone and often to darker brown in localised areas where water penetration occurs through neglect. It is an oolitic limestone but the ooliths (spheres) are not readily visible. The stone occurs in distinct beds known as Portland Base Bed, Portland Whitbed and Portland Roach. Fossils are prominent in most Portland stone and, as natural weathering occurs, the harder fossils tend to stand proud of the surrounding matrix.

Sedimentary Rocks and Fossils

Portland Stone, as mentioned above is a Jurassic Limestone - which is a type of sedimentary rock. 

One very interesting feature found in sedimentary rocks are the presence of fossils. A fossil is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved in amber, hair, petrified wood, oil, coal, and DNA remnants.

There are 4 types of fossils:

• Mold fossils (a fossilized impression made in the substrate - a negative image of the organism)
• Cast fossils (formed when a mold is filled in)
• Trace fossils/Ichnofossils (fossilized nests, gastroliths, burrows, footprints. Anything not of the organism, but proof that it exists!)
• True form fossils (fossils of the actual animal or animal part).