Dudley - Crown Jewels Of The Trilobite Kingdom

The keep at Dudley Castle on a verdant hill, beside a large tree.

The Keep at Dudley Castle

     The scene would probably have appeared somewhat strange to our contemporary eyes. There they all were… men, women and children, each attired in their late-19th Century Sunday's Finest, scurrying through the rough, rocky Silurian-age outcrops of Wren's Nest, located near the quaint town of Dudley, deep in the heart of England's coal-rich Black Country. They were all searching for one thing… to what their eyes appeared to be insects that had been miraculously turned to stone. 
     Some among this intrepid group of visitors may have had the forethought to carry along a small hammer with which to break apart any interesting looking rocks they might encounter. Others may have brought a hand-held lens through which to better view their potential finds. But most strolled through the rugged terrain of Wren's Nest for the sheer joy of adventure and discovery, hoping that a prized specimen would both literally and figuratively fall under their well-honed feet. 

     Today we might find the notion of hunting for fossils without the requisite array of work boots, chisels and kneepads somewhat disconcerting… if not downright dangerous. But back in the 1800s, when such high-society outings were a weekly occurrence at these now-famed Wenlock limestone quarries, searches for what were then known as Dudley Locusts -- and now recognized as the trilobite Calymene blumenbachii-- were on the cutting edge of both family holiday fun and true scientific research.     
     Some of these early adventurers grew so enamored with the incredibly diverse fossil array to be found at Wren's Nest that they began to spend more and more of their free time scouring the location, in the process amassing some of the most impressive Dudley fossil collections ever recorded. In fact, such was the era's enthusiasm for the Wren's Nest fauna that when the famed Scottish geologist Sir Roderick Murchison (author of the groundbreaking 1839 volume, The Silurian System) would lecture on Dudley's fossils, his talks would often attract incredible throngs. One such talk, held at Wren's Nest itself, drew an estimated crowd of 15,000, after which Murchison was carried triumphantly about by his frenzied followers and declared the King of Siluria. Over the ensuing decades hundreds, if not thousands, of complete trilobite specimens --representing 80 different species -- were uncovered, with many of these beautifully preserved Paleozoic remnants ending up not only in museum displays around the globe, but also being handed down from generation to generation as prized family heirlooms. 

     “Many of the trilobites that were found centuries ago have been maintained in private cabinets of curiosity to this very day,” said Alf Cawthorn a noted British trilobite authority. “It's still not unusual to see a Dudley fossil come up at an English estate sale or auction. A number of Calymene blumenbachii actually became the centerpieces for jewelry back in the 19th century. People of that era may not have known exactly what they were wearing, but they certainly knew it was something different and unusual.”
     The fact is that the sedimentary outcrops in and around the Dudley area have been extracted, examined and collected for nearly a millennium, with the Wren's Nest location now ranking among the most renowned paleontological sites in all of Europe. Initially the quarrying of the area's thick limestone layers was not undertaken with fossils in mind; rather it was done to acquire building materials for some of the town's most ambitious architectural projects. Indeed, many of the area's more famous landmarks -- including nearby Dudley Castle, built early in the 12th Century -- have been constructed solely out of the Silurian-age limestone blocks brought forth from the nearby hillsides. Over the ensuing centuries these rocks were also found valuable for somewhat less ambitious purposes -- primarily as quicklime fertilizer for many area farms, and later as an essential ingredient in the manufacturing of iron, for which the English midlands are justly famous. 
     Understandably, those who first explored these layers were both confused and confounded by the numerous fossils they encountered. They may have recognized a brachiopod or even a flower-like crinoid for what they were -- or at least what they thought they were -- but a trilobite? There's simply no way that these early pioneers could have imagined that they were having a close encounter with the signature life form of Earth's early history, a creature that had lived more than 400 million years ago… back when the area was far different than it is today. To them, these strange “bugs” made of stone must have appeared like talisman from some distant and mysterious time.
     Quarrying of these rocks continued on virtually unabated through the ensuing centuries. But it wasn't until the dawning of the 1700s that a few intrepid souls began to more closely investigate these outcroppings and appreciate the wide variety of life forms -- especially trilobites -- that they held. Back then, eons of weathering of the hard limestone layers had freed so many trilobite pieces (usually disarticulated cephalons or pygidia) from their ancient burial sites that they practically littered the ground. 
     It is highly unlikely that any of these early naturalists possessed even the slightest clue regarding the true age and importance of these ancient relics. Even fewer would have dared to imagine that back in the Silurian, the roughly 25 million year-old epoch that stretched from 443 to 417 million years ago, the areas that now comprise the English midlands were situated beneath a shallow semi-tropical sea which covered the picturesque hillsides upon which they now stood. Yet the lack of such information did little to deter the enthusiasm possessed by these pioneering adventurers. Over the following centuries, as interest in the natural sciences began to grow within England's upper classes, collecting fossils in and around Wren's Nest become something of a cottage industry, with local residents often setting up small road-side stands that offered up a variety of Paleozoic morsels as souvenirs to those weekend visitors not inspired enough to actually go searching themselves.
     “There are stories of well-to-do families leaving church on Sunday afternoon, and taking a leisurely coach drive up to Wren's Nest,” said one current Dudley resident. “They would proceed to walk throughout the area searching for fossils and other oddities. A number of locals would tend to this trade by selling their wares-- including their own fossils-- along the road to and from the rock outcrop.”
     The fact that these Dudley specimens are Silurian (named after an ancient Welsh tribe that inhabited what is now Wales) makes them of particular significance to both collectors and paleontologists. That particular period of earth history was the shortest, and perhaps least "glamorous" of the various Paleozoic ages. Unlike the Cambrian, which holds particular scientific cachet for bearing witness to the initial flowering of multi-cellular life, or even the Devonian, during which a myriad of ever-more-familiar looking creatures began to rear their often bizarre heads, the Silurian was a period marked most notably by global climatic stabilization and a significant increase in world-wide sea levels. Yet judging by the diverse life forms that fill Dudley's Wenlock outcrops, it is rather easy to surmise that the climate back in the mid-Paleozoic was quite different from the blustery, cool temperatures that dominate the region today. 
     In fact, recent magnetic mapping of the area shows that back during the Silurian, present-day Dudley lay within 30 degrees of the equator.  Fossils of corals, crinoids, echinoderms and brachiopods -- as well as the ubiquitous trilobites -- give further proof that this was once a warm costal plane, a tidal estuary that provided a perfect environment for the proliferation of life forms both common and exotic. And it is even more apparent that the waters in and around Dudley were a haven for trilobites, with species such as Bumastus barriensis, Dalmanites caudatus , Acaste downingiae and Encrinurus tiburculata thriving in the rich ocean climate. 
     During the Silurian, the waters in and around Dudley were clearly brimming with life, and due to the centuries of excavations that have taken place at Wren's Nest, few other paleontological pockets in the world -- including New York State's equally rich Silurian outpost, the Rochester Shale -- have had their flora and fauna as well chronicled and documented. Yet what is perhaps even more important to scientists and collectors around the globe is the manner in which these ancient organisms were preserved once they perished and sank into the thick mud that covered the bottom of the shallow sea that then enveloped the area. After all, many sedimentary locales throughout the world are filled with fossils, yet too often these remnants are little more than disarticulated bits and poorly-preserved pieces. Due to gentle currents that existed in the Wren's Nest estuary's surrounding waters, however, Dudley's fossils were allowed to rest in a relatively undisturbed state as they were slowly covered by layer-upon layer of sediment. 
     Over the ensuing eons, these sediments were painstakingly transformed into well-defined limestone layers by the internal forces housed within Planet Earth. Yet despite the incredible compression and shearing torque that so frequently accompanies such a fossilization process, the trilobites of Dudley have become world-renowned for their amazing state of three-dimensional preservation. Their shells are comprised of a beautiful toffee-hued calcite, their detailed compound eyes (some featuring as many as 100 individual lenses) and delicate spines preserved with intricate detail. And after some skilled preparation work is done in order to remove what remains of their surrounding hard rock matrix, today these ancient “butterflies of the sea” look little the worse for their 400-odd million year sojourn through time. 
     “What is particularly amazing about the trilobites from Dudley is the amount of detail they possess,” Cawthorn said. “Even centuries ago, when the specimens were cleaned by hand rather than with modern preparation equipment, it was easy to see the compound eyes on the phacopids, and the delicate spines on the odontopleurids. In fact, Dudley trilobites have always presented one of our best looks back upon Silurian trilobite morphology.”
     Today, just about any major museum or private trilobite collection will feature a variety of specimens derived from the fossil-rich Wenlock limestone layers. The ubiquitous “Dudley Locust” is still the most famous -- and most common -- species found. Yet over the decades an almost dizzying array of other trilo-types have been uncovered in the Wren's Nest locale with these ranging from the large homalonotid Trimerus delphinocephalus, which has been known to exceed 15 centimeters in length, to the diminutive bubble-nosed cheirurid Deiphon barrandei, which rarely grew larger than 3 cm. 
     Somewhat surprisingly, many trilobite examples found back in the 19th Century -- when the concept of preparation often involved the hand wielding of everything from knitting needles and nails to rather cumbersome dental tools -- still hold their own in terms of quality, rarity and desirability. Indeed, the trilobites found during those early digs hold a particular cachet among enthusiasts who will often seek out so-called “Victorian Collection” pieces and choose them over more recently discovered, air-abrasive prepared Dudley examples. 
     Yet whether certain trilobites were found 200 years ago, or last Thursday, with the Wren's Nest location now having been designated as a United Kingdom geologic Site of Specific Scientific Interest -- with anything more than surface collecting now banned, and even that often frowned upon by local authorities -- the uniqueness, beauty and scientific significance of the area's fossil fauna has become more appreciated than ever. The simple fact of the matter is that Wren's Nest trilobites remain among the most desired fossils in the world -- especially by Paleozoic connoisseurs who revel in both the history and allure of these magnificent pieces of natural science. So even two centuries after those well-dressed Sunday visitors first began exploring the area's rich Silurian outcroppings, Dudley, England, proudly retains its title as one of the Earth's premier paleontological sites. That is a distinction it will clearly not relinquish any time soon. 

Fossilized ripple markings on Wren's Nest, a limestone mountain.

Wren's Nest - Fossilized Ripple Markings

Photo credits: Top; Keith Leatham  Bottom; Andrew Tenny

Click here for The Gallery of Dudley Trilobites

Illustration of the shield & crest of Dudley County with two winged figures flanking a crest with a dragon and castle on it, topped with a lion.

Shield & Crest of Dudley County with a representation of a "Dudley Locust"