The Builth Inlier of central Wales is internationally famous for its trilobites, an extinct group of vaguely (but misleadingly) woodlouse-like creatures. However, it was also home to a bewildering variety of other creatures, many of them undeservedly obscure. The rocks of the area were deposited in the Middle Ordovician (c. 465-455 million years ago) and record the formation and erosion of a volcanic island complex.

An ancient fault plane in the volcanic Llandegley Tuff Formation of Llandegley Rocks.

The rocks range from ‘normal’ Ordovician graptolitic shales to coarse volcanogenic sandstone dominated by sponges, and the number of subtly different ecosystems is remarkable. This variety of environments, each complete with a diverse collection of well-preserved organisms, allow us to reconstruct a lost world in more detail than is normally possible. The fossil faunas of the inlier have been studied in great detail over the past 300 years (and especially the last 100), but only now are we beginning to realise how little has yet been discovered. The unique insights gained into Ordovician ecology, evolution and palaeobiology are of global significance.

This website is an introduction to the fossils of the Builth Inlier in particular and the Ordovician in general. It is a broad resource base that includes a general introduction to various fossil groups (Introduction/groups and Research/Faunal list) and to the geological history of the inlier (Research/stratigraphy), and detailed information on identification of Builth Inlier species (Research/Faunal List).

A rather nice specimen of the trilobite Cnemidopyge parva. The only parts missing are the fragile spines that come off the back of the head (see the faunal list if you want to know what they would have looked like).

For the specialists, we provide a comprehensive reference list for the fossils of the inlier, and the completeness of the record is intended to stimulate research ideas, and encourage yet more information to emerge. The really detailed stuff is on the 'Research' page, including an ongoing, 'complete' faunal list of both described and undescribed fossils. The aesthetic qualities of the less well-known fossils are often overlooked, but we hope to give them some limelight with the image gallery. There is a teaching section particulary for A-level and undergraduate teachers, with suggested exercises using the data from the site. There is also a forum for discussion of palaeontology and geology, particularly of the Ordovician of Wales, and including an online identification service.

One of our aims is to treat the ecosystem holistically, in a way that reveals it in an intuitive way. This approach is often overlooked by academics, who of necessity must focus on just part of the story, so that the entire vista is rarely encountered. We hope to present a perspective that can be appreciated by scientists and occasional collectors alike, making the experience more than merely intellectual. We want you to see the Ordovician come alive.

Don't forget the jellyfish repellent!

Essays and other things:
Fossil Preservation
The Rise of the Sponges
Dating Techniques
Full fathom five... or five hundred?
The Faunal List - Why?
Identifying fossils
Fossil preparation and conservation
The Builth Inlier - for beginners!
Getting into palaeontology
Snakes and Ladders and cornutes
Beginners' Guide to Fossilologizing
Basic key to fossil groups
About Us