Christchurch sits beside two eroded volcanoes whose craters the sea flooded to make Lyttelton and Akaroa harbours. The geology, the French, the dolphins and the bays behind the hills.
Look at Christchurch on a map and the city sits on a flat plain with one strange lump attached to its side, a knot of hills and inlets like nothing else on the coast. That lump is two volcanoes, and the two long harbours cut into it are their flooded craters.
Banks Peninsula is the most geologically interesting hour of driving in Canterbury, and almost none of it is signposted. Here is what you are looking at.
Two volcanoes, worn to half their height
Lyttelton came first, erupting between roughly twelve and ten million years ago. Akaroa followed to the south, larger, active for a few million years after that and perhaps fifty kilometres across. Both were built out at sea, an island of dark volcanic rock off the Canterbury coast.
When the eruptions stopped the cones wore down to about half their height, and rain cut deep radiating valleys into the flanks. Later the sea pushed up the two largest of those valleys and into the breached craters. Lyttelton and Akaroa harbours are drowned valleys inside collapsed volcanoes, which is why they run so straight between hills of such uniform steepness.
Cook's island that was not
James Cook charted this coast in February 1770 and drew the peninsula as an island, naming it for the botanist Joseph Banks. He was not being careless. It had been an island, and had only recently stopped being one.
The braided rivers pouring off the rising Southern Alps have been dumping gravel onto this coast for a very long time. That gravel built the Canterbury Plains outwards until it reached the old volcanic island and tied it to the mainland. Christchurch is built on the join. Ngāi Tahu know the peninsula as Te Pātaka o Rākaihautū, the storehouse of Rākaihautū, and Ōnawe, the headland at the top of Akaroa Harbour, still carries the remains of a pā.
The Summit Road, and the man who wanted it
The road along the crater rim above Lyttelton is essentially one man's idea. Harry Ell, a Christchurch member of parliament, campaigned through the early twentieth century for a public road along the tops with rest houses a comfortable walk apart. Several were built and several survive, still carrying their working names: the Sign of the Takahe, the Kiwi, the Bellbird, the Packhorse.
From the rim you have the harbour on one side with the ships in it, and on the other the whole plain running out to the Southern Alps. Our Port Hills guided walk and city tour is NZ$815 per person and takes in the rim on foot as well as the city below.
Akaroa, and the French who arrived second
In 1838 a French whaling captain, Jean François Langlois, negotiated what he believed was the purchase of much of the peninsula, then sailed home to raise a settlement company. The Comte de Paris reached Akaroa in August 1840 with around sixty French and German settlers. By then the British had moved: HMS Britomart raised the flag at Akaroa on 11 August 1840, days before they arrived.
The French stayed anyway and farmed, and the town they left is still legible. The streets are Rue Lavaud, Rue Jolie, Rue Balguerie and Rue Benoit and the old French cemetery is up the hill. A guided Akaroa day trip from Christchurch is about ninety minutes each way, over the rim at Hilltop where the whole harbour opens at once.
Hector's dolphins in a drowned crater
Akaroa Harbour holds a resident population of Hector's dolphins, the world's smallest marine dolphin, found nowhere outside New Zealand. They are pale grey with black markings and a rounded dorsal fin unlike any other dolphin. The Banks Peninsula Marine Mammal Sanctuary was established around them in 1988.
They are in the harbour all year. An Akaroa scenic harbour cruise also runs out to the volcanic sea cliffs, the caves and the little blue penguins on the outer coast, and our guide to Hector's dolphins and where to see them covers where to look.
Behind the hills: the bays, the vines and the bush
Radiating out from the two craters is a set of bays most visitors to Akaroa never see, each at the bottom of its own steep narrow road. Okains Bay has a long sand beach and a museum with a significant Māori and colonial collection. Pigeon Bay runs a long finger north into the Lyttelton crater. These roads are slow, single lane in places and unfenced above the drop, which is why many self-drive visitors turn round at the top of the first one. It is also where a private Akaroa tour earns its keep.
Volcanic soil on north-facing slopes gives the peninsula a handful of very small vineyards, mostly around warmer bays such as French Farm. The same soil once grew enormous podocarp forest, and the mills and fires of the nineteenth century took nearly all of it. Above Ōtānerito Bay, Hinewai Reserve has spent since 1987 proving it can come back, letting gorse stand as a nursery canopy under which native seedlings germinate and eventually shade it out.
Common questions
Is Banks Peninsula a volcano?
It is the eroded remains of two overlapping volcanoes. The older Lyttelton volcano erupted from roughly twelve million years ago and the larger Akaroa volcano followed, staying active for a few million years after that.
Why did Captain Cook map Banks Peninsula as an island?
Because it had been one. Cook charted the coast in February 1770 and named it for the botanist Joseph Banks. Gravel carried down by the Waimakariri and other braided rivers built the Canterbury Plains outwards and joined the old volcanic island to the mainland.
Why is Akaroa a French town?
A French settlement party aboard the Comte de Paris arrived in August 1840, following a purchase negotiated by the whaling captain Jean François Langlois in 1838. Britain had already asserted sovereignty, raising the flag at Akaroa on 11 August 1840, but the settlers stayed and their street names and cemetery survive.
Where can I see Hector's dolphins on Banks Peninsula?
Akaroa Harbour holds a resident population year round, within the Banks Peninsula Marine Mammal Sanctuary established in 1988. Harbour cruises from Akaroa are the most reliable way to see them.
The peninsula rewards a slow day and a guide who can tell you which crater rim you are standing on. See our Christchurch luxury tours for the private option, compare it with the coast north in Akaroa or Kaikoura, or get in touch.
