He finds seashells by the seashore

Most tourists who visit Hornby Island make a beeline for the warm waters of Tribune Bay. They visit in the summer months to relax with their toes in the sand.

And then there’s eleven-year-old Sandy McLachlan, mid-morning on March 7, 1998. It’s four degrees Celsius, cloudy, with a slight breeze from the north. He leads his father down a narrow footpath to Collishaw Point on the island’s northernmost tip.

The beach is gray, worm-pitted siltstone, algae smothered and barnacle encrusted. A place internationally renowned for its abundance and exquisite preservation of fossils.

Concretions containing fossils

McLachlan spies a concretion stuck in a low wall. Concretions are hard nodules found in sedimentary rock like siltstone or sandstone. Sometimes, but not often, they contain fossils. On this beach the concretions wait in situ or have become dislodged to roll in and out with the tides.

A good crack from the boy’s geology hammer reveals a bivalve last alive during the Late Cretaceous.

Next, he notices a concretion with the end knocked off by a previous collector. Inside is a fragment of the ammonite Baculites occidentalis. Ammonites are extinct mollusks related to modern-day squid, octopus, and nautilus. They died out with the dinosaurs. But collectors here can find a variety of their fossilized shells.

One rare and highly sought-after type is named for the island—Nostoceras hornbyense. Well-preserved specimens still contain the many defensive spikes adorning their curled and trombone-shaped shells.

With intact specimens like this waiting on the beach, it’s easy to see why the previous collector left the fragment young McLachlan found. He rubs his thumb over its smooth ridges, still surprised someone would just leave it. He suspects he has much to master when it comes to collecting fossils.

Learning from a renowned fossil collector

A few years later, McLachlan’s mother learned that her boss, Rick Ross, could help. It turned out he was a renowned fossil collector—just the guy to teach McLachlan some tips and tricks.

McLachlan joined Ross on trips to Hornby and other collecting areas. On these trips Ross would explain the local paleontology, details that would bore most teens. He was surprised when the young man asked questions. Ross had found someone who shared his fascination with fossils, and his protégé soon became a competent collector.

On the tail end of 2008 and one of its December storms, McLachlan headed to Collishaw Point in search of concretions. Storms sometimes carry them high onto the beach since they are lighter than igneous rock.

He plucked one from the rubble. Usually, no fossil material protrudes outside a concretion; most collectors give only a quick glance to the outside or don’t look at all. Before he smashed it between hammer and boulder, McLachlan inspected the outside. He didn’t want to obliterate something important.

Finding pterosaur remains

Around 72 million years ago, a delta deposited material into this offshore environment. Vertebrates, animals with backbones, are rare finds. Rarer still are creatures not at home in the water. But when McLachlan flipped that concretion over, he noticed the ends of hollow bones sticking out. Hollow bones are an evolutionary adaptation for creatures that fly. Two creatures could have left them: a bird or an extinct flying reptile called a pterosaur.

Eight long years later, in 2016, McLachlan was halfway through his Master of Science thesis at UVic (he studied Hornby Island fossils) when paleontologists from the UK announced the remains he had found belonged to a pterosaur. It is the smallest azhdarchid pterosaur ever found.

A collector in modern times has it tough. Folks have been scouring the north end of Hornby for fossils since the 1960s. Prior to that, geologists with the Geological Survey of Canada had only to walk the beach and take their choice of concretions.

Searching beyond the low-tide mark

In 2018, McLachlan, now 30 years old, stood waist deep in the water just offshore from Collishaw Point. Dressed in a wetsuit, he watched a diver named Gord Cooney slip under the surface. The plan was to search where few had—beyond the low-tide mark.

McLachlan had met Cooney months earlier. The diver and marine engineer had connections to Hornby, but knew little about fossils.

While McLachlan waited up top, an airbag rose to the surface, followed by another. Each was attached to milk crates stuffed with concretions—over 100 between them, more than McLachlan could find in a week on the beach.

They swam the crates to dry land, and McLachlan reached for the mini sledgehammer that lives in his belt holster.

One sharp blow. Salty sea water spattered McLachlan’s glasses and mouth. The concretion popped open—it was empty, as most are.

Even after this, he found more places to search. This time he zoomed in.

The resting stages of microscopic phytoplankton

McLachlan wrote his PhD thesis on the resting stages of dinoflagellates, microscopic phytoplankton. Paleontologists measure them to determine the age and geology of ancient earth, looking for big answers from the smallest fossils. During his studies at UVic, he visited Hornby and other significant fossil exposures in the area to reconstruct these ancient marine environments.

With collectors like McLachlan around, it might seem like Hornby’s beaches have been picked clean. Siltstone, however, is relatively soft, and, with storms battering the shores, new fossils are exposed every winter. If you decide to visit, be sure to pick up a copy of Rolf Ludvigsen and Graham Beard’s West Coast Fossils from the Hornby Island Natural History Centre or the Courtenay Museum. It contains essential information for a successful outing and is the go-to resource for local collectors.

On your adventure, keep an eye out for someone diving just offshore—McLachlan considers his mission still incomplete.