OS grid reference: SD 80919 44434. Something of a curiosity this one, maybe. In the wall along a stretch of the lane that runs through the long, narrow valley between Twiston and Downham, at the north-western side of Pendle Hill, in Lancashire, are lumps of locally quarried ‘Fossiliferous Limestone’ made up of crinoid and coral fossils, which date back some 500-300 million years to the Carboniferous period in Geological history. But what a delight it is to just wander along the lane looking at the fossil-covered stones that make up the walls, and there are literally thousands and thousands of them to be seen here.
These crinoid fossils are very varied in shape and form, but they are in essence tiny marine creatures which originated from the sea – so we know without doubt that this area was under water millions of years ago, with perhaps only the top of Pendle Hill visible at that time. The stones that make up the walls in Twiston may have been quarried from the Limestone ‘reef knolls’ – of which there are several in the Twiston and Downham area, or perhaps from Peach Quarry at Clitheroe (Os grid ref: SD 7569 4263). This quarry has now been filled in and grassed over. These ‘reef knolls’, as the name suggests, were also under-water millions of years ago.
There are ‘still’ three 19th century lime kilns in the Downham area; one of these stands beside the lane at Twiston, all of which points to the fact that Lime, in the form of a powder or “cornbrash”, was a much used local neccessity on farmers’ fields in the Pendle area, and is still used by local farmers today.
A significant feature of the valley landscape between Twiston and Clitheroe is the abundance of Crinoid Fossils in the stones making up the walls of field boundaries. This type of stone is called ‘Reef Limestone’. Crinoids are sometimes referred to as ‘sea lilies’ because of their resemblance to a plant or flower. In parts of England, the columns forming the stem were called ‘fairy money’, and their star-shaped cross sections was associated with the sun by ancient peoples, and given religious significance; indeed ancient people were said to be frightened by these strange fossil forms, as they did not know or realize what they were, and where they had originated.
Crinoids are in fact marine animals belonging to the phylum Ecinodermata and the class Crinoidea. An array of branch-ing arms (brachials) is arranged around the top of a globe-shaped, cup-like structure (calyx) containing the mouth and main body of the animal. In many fossil forms the calyx was attached to a flexible stem that was anchored to the seabed.
The phylum Echinodermata includes the starfish, sea urchins and sand dollars. The crinoids are a breed apart however, as they resemble an underwater flower. Some even have parts that look and act like roots anchoring them to the ocean floor. They are commonly called ‘sea lilies’. Their graceful stalks can be meters long. Other varieties have no stalks or root- like parts. They are commonly known as feather stars. Unlike the sea lilies the feather stars can move about on tiny hook- like structures called cirri.
Crinoids are still with us, but they are also some of the oldest fossils on the planet. They flourished in the Palaeozoic Era 541-254 million years ago. Although sometimes different in appearance from their fossil ancestors, living forms provide information about how fossil crinoids must have lived. The earliest come from the Ordovician the second period in the Palaeozoic. At least the earliest that everyone agrees on. There is a class called Echmatocrinus that date back to the middle of the Cambrian Period the first period in the Palaeozoic, but most palaeontologists don’t count them to be true Crinoids. Most of the Palaeozoic forms died out in the Permian the final period in the Palaeozoic Era. The few species that survived into the Mesozoic Era thrived. Many new species evolved during this time including the ancestors of the present-day class Articulata.