This is a buff-grey quartzite, which includes sandstone and coarser, conglomeratic beds, and has excellent crossbedding. Above this unit, red and green shales outcrop on the beach. As you move north toward the base of the bluff, you will see green limestone as the next younger unit. This is followed by red limestone containing lighter coloured nodules and layers of fossil algae in an interesting pattern. The topmost unit is red shale, seen in the cliffs above the road.
All of the beds dip westerly. They were deposited in seawater that changed in depth over time, from the shallow, near shore environment of the quartzite, to the deeper water environment of the shale, and then to the lagoonal habitat in which the algae lived.
The large rocky slabs offshore are made of Late Proterozoic shale and sandstone and have been cut by broad white quartz veins.
Turn north off the TCH at Route 63 (Avondale access road) and turn left at its junction with Route 60 (CBS Highway). Drive 3.1 km, turn right toward Conception Harbour and drive a farther 6.3 km to Little Bacon Cove, parking on the road above the wharf. Make your way down the bank to the rocky platform on the right.
The irregular flat shelf you are standing on is an erosion surface cut into steeply dipping, grey-green, Late Proterozoic siltstone. The hollows are filled with pockets of Cambrian conglomerate and red shale. The ledges at the back and just along to the south consist of algal mats and limestone lenses in the Cambrian shale. Algae are primitive plants that built irregular layered colonies (mats) as mud accumulated on the ancient sea floor. The Cambrian rocks dip gently to the west.
The geologic sequence is as follows: 1) Proterozoic silt was deposited on the sea bottom, and was then buried by later sediments and hardened into rock. 2) Mountain building in Late Proterozoic time folded, tilted and uplifted these rocks, which were then eroded to a roughly flat surface. 3) In the Cambrian, pebbles and then mud were deposited as the sea flooded across the erosion surface, and algae flourished in the shallow seawater. 4) Burial and hardening of the new sediment into rock was followed by more mountain building, during which the Cambrian sedimentary rocks were also tilted, uplifted and eroded. 5) Quaternary glaciation provided the latest cycle of erosion, exposing the surfaces we see today. Modern weathering and erosion by waves are continuing to crack off blocks from the shore ledges.
The hills have a severe local climate, because of their altitude and extreme exposure to strong, cold winds; heavy fog is common! The vegetation is characteristic of arctic/alpine regions, and active frost boils are found.
Drive to Branch via Route 92 or 100. West of the bridge over the river in Branch, turn south toward the coast, and park by the shore. You can walk along the beach at the base of the cliffs except at the highest spring and fall tides. Examine the colourful red and green shales in the cliffs. The green shale contains several species of trilobites within 300 m of the community. About 1 km along the shore, almost out at Branch Head (the prominent headland to the south), is black shale that is slightly younger and also contains trilobites.
From the TCH, drive south on Salmonier Line (Route 90) to the church in the centre of St. Mary's, and turn right. Drive 0.7 km, and turn left up the hill by the end of the barachois; turn right at the top of the hill, then take the left fork in the road. Park at the end of the pavement, and walk 0.5 km along a rough track to a gate in the fence on the right just past a small hut on the cliff top. Walk through the gate to the cliff top path and turn left, following the path a short distance to a prominent point of red mudstone and mixtite. The straight side of the point is formed by a fault.
Beyond the point, the cliffs are very steep for perhaps 100 m, then it is possible to scramble down to the rocky beach below to examine the geology more closely. The red mixtite was deposited on a steep underwater slope and consists of sediment carried out to sea by a floating, melting ice cap in Late Proterozoic time. As the deposit accumulated, the pile became unstable and slid down the slope, to become a chaotic mass at the bottom. A few layers of mudstone and sandstone indicate intervals of quiet sedimentation.
Boulders in the mixtite are up to a metre across and are of many different rock types, including granite, volcanic rock and mudstone. Most of them can be traced to older formations on the Avalon Peninsula, but a few are "exotics" that have come from outside the area. Some of the boulders show signs of ice movement, such as striations and facets (flat sides).
The shore closer to St. Mary's is not as steep, and is more easily accessible. There the same formation consists of bedded siltstone and sandstone. A plaque is erected on a grassy knoll to mark the location of St. Mary's Battery, which protected the local inhabitants from raiding American privateers between 1779 and 1815.
The Mistaken Point area is remote and the last few settlements were abandoned in the late 1950s. The headland is a wild and beautiful place for a day hike for the more active person; it is well worth the effort.
Drive to Portugal Cove South, and take the gravel road southeast from there for 14.7 km toward the Cape Race lighthouse. A steep hill at the abandoned settlement of Drook requires special caution. Just before Long Cove (also abandoned), a good track heads back west toward the headland of Mistaken Point. Park just off the road, and walk the 2.5 km, passing the commemorative bronze plaque. If it is windy, your walk may be accompanied by the eerie hooting of the buoy off the point.
At the headland, great slabs of grey and purple sandstone, siltstone and shale are tilted seaward. Cleavage and fracturing at right angles to the bedding give the rock surface a "rippled" appearance. The fossils are visible on some of the bedding planes on the west side of the point. The accompanying sketches show what the fossils look like. Some are more than 20 cm long and are somewhat similar to modern jellyfish and sea pens. They lived in the sea near an ancient continent where volcanic activity was frequent. Ash erupted by the volcanoes was deposited as thin beds and may be the reason the fossils are preserved, burying them in action, so to speak. Remnants of ash beds have a rough feel, and occur as patches on the bedding planes where the fossils are found.
A previous visitor has framed some of the better fossil examples. Please treat these rare relics of ancient times with the respect they deserve, and do not scrape or disfigure them.
Warning! Mistaken Point is an Ecological Reserve and fossil collecting is not permitted. Sea cliffs and marine currents are dangerous. Exercise extreme caution.
Glaciers scoured this landscape between 23,000 and 9,000 years ago, smoothing and rounding the hills all around the western horizon, and gouging out St. John's harbour, the Narrows, and Quidi Vidi Lake.
A trail leads from the parking lot at Cabot Tower, down the front of the hill facing the ocean, and around the cliffs by the Narrows to the Outer Battery (a historic fishing village within the city). Along the trail are beds of sandstone and conglomerate that have been smoothed and polished by glaciers.
From the main parking lot, walk out to the World War II gun emplacements. Gently west-dipping conglomerate contains rounded pebbles of volcanic rock, and is interlayered with sandstone. You can see it well above and beyond the guns, and (from a safe distance) down below on the shore. The conglomerate is on the eastern arm of a giant fold which has been tilted to the north. It continues under the sea to join up with conglomerate at Petty Harbour and Signal Hill.
Northward toward the lower parking lot, the rocks become younger. As they do so, the conglomerate gradually gives way to sandstone, until the rocks consist entirely of sandstone interbedded with shale. You can see the gentle dips of the beds in the cliffs to the north across the cove.
The beach area immediately north of the ferry terminal is backed by high cliffs of Ordovician shale and crossbedded sandstone, appropriately called the Beach Formation. These rocks were formed in an ancient tidal environment where a variety of animals lived. Signs of these animals may be seen in trilobite tracks, worm burrows and shell fragments on the flat surfaces of fallen slabs.
Drive on up the steep hill from the wharf, turn right on East End Road, then right on Lighthouse Road to visit the lighthouse at the north end of the island. Park at the barrier and look east at the cliff face on the large detached block. The same reddish, gently dipping beds seen on the beach are present below, overlain by a band of grey, quartz-rich sandstone.
Proceed back along Lighthouse Road, turning right at East End Road, and follow it into the town of Wabana. Several large murals on public buildings depict scenes from Bell Island's history. The oldest open-pit iron mine, opened in 1895, lies off to your right as you drive straight through the town. Surface ore ran out in 1902, and mining descended underground, following the west-dipping, iron-rich layers as far as 3 km out under Conception Bay toward Carbonear. Beyond the west end of Wabana, just before the Trade School and another mural, Airport Road branches right. A short distance down it, to the right, is the entrance to one of the inclined shafts, dating from 1916. The iron mines eventually closed in 1966.
Lance Cove, on the southeast side of the island, was first settled by farmers and fishermen in the early 1700s.
To visit the site, take Pitts Memorial Drive or Route 60 out of St. John's as far as the bridge over the Manuels River at Manuels. Park at the south end of the bridge and walk down the trail to the river. The whole series of rocks can best be seen when the water is low.
Above the highway bridge, the river flows over Late Proterozoic granite and volcanic rocks. Below the bridge, the falls cross Cambrian conglomerate, which lies unconformably on the Proterozoic rocks (see sketch) and consists of granite pebbles. The conglomerate is about 6 m thick, and together with the overlying shales, dips gently northwest. As you follow the trail downstream across and beyond a footbridge, the rocks are progressively younger, ranging through green-grey and red mudstones or shales to grey-black, fossil-bearing shales (Manuels River Formation).
If the water is low enough, you can continue down the east bank (about 1 km) all the way to the fossil-bearing black shale beds. If the water is high, follow the trail up and along the top of the east bank to more steps that go down to the river between the two fossil beds. Trilobites (see sketch) grew by periodically shedding their outer shells as do modern crabs and lobsters; you are more likely to find discarded pieces of shell than the whole animal!
Newfoundland and Labrador Traveller's Guide to the Geology
Edited by: S. Colman-Sadd and S.A. Scott, 91 pp. + map, 1994