I recently received an email from Sheila in New Hampshire requesting some tumblestones that she could send to friends. I selected 30 polished stones from three South Island beaches to send to her. In Part One of this series of Posts, I described the ten I sent her from Gemstone Beach while Part Two described the ten from Kakanui. This Post describes the ten from Birdlings Flat.
Birdlings Flat is a small village and beach just south of Banks Peninsula, half-way up the east coast of the South Island (see map below). The Peninsula is of volcanic origin but the Flat is located on the far eastern end of a large gravel spit called Kaitorete Spit.
Kaitorete Spit is about 25 kilometres long, cutting off a large lake from the sea:
Over a period of approximately 5000 years, Waihora/ Lake Ellesmere became first a bay, then an estuary and finally a lake, enclosed by the distinctive Kaitorete Spit, a long, narrow barrier of sand and shingle. The beach barrier, or ‘spit’ as it is known, is broadest and feels least exposed where it connects to the volcanic ‘mainland’ at the edge of Lake Forsyth. It tapers to a tenuous connection in the south where the lake is able to be artificially opened. (From “Banks Peninsula Landscape Study”, 2007, page 194.)
The beach at Birdlings Flat is perhaps the most well-known among stone fossickers in New Zealand. A great range of stones have been brought down to the sea from the Southern Alps by half-a-dozen rivers to the south, including stones from Kakanui (250 kilometres away) and even further south. For millions of years coastal currents have swept the stones north to pile against the basalt cliffs of the Banks Peninsula and to form Kaitorete Spit. In her book “The New Zealand Rockhound”, as long ago as 1981, Natalie Fernandez captures the character of the beach accurately when she wrote:
Hundreds of rockhounds have cut their teeth on Birdlings Beach – just a short run from Christchurch. Here great rollers break on the stony shore throwing forward stones with a roar as the waves thunder up the steeply shelving beach and sucking them back with a clatter as the waves recede. You can look for your agates and jaspers well back from the water-line but they do not show up clearly unless you dig down, for only the surface layer is dry. More exciting is to hunt along the water’s edge. As a wave slides back an agate is spotted. You leap for it but miss as the next wave roars in, driving you back. You never see that agate again. The beach is steep and the undertow strong. The breakers are especially powerful in a southerly and on the in-coming tide. Few can play this game and keep dry. (page 14)
Three videos on YouTube provide a good idea of the beach, its setting and its stones. The first one is nearly eight minutes of drone footage, showing the Birdlings Flat end of Kaitorete Spit. The second one provides a beach level view, just over one minute long, taken on a sunny day with a number of people enjoying the beach. The third one, 2 ½ minutes in duration, shows a stone fossicker hunting for beach agates.
I have visited Birdlings Flat three or four or more times a year since 2016, looking especially for agates and quartzites and jaspers but finding also a range of other interesting stones. I am sending ten of these stones to New Hampshire, some of them being nice quartzites. Here are the first five:
The second set of five stones from Birdlings Flat:
In the Introduction to Josie Iselin’s book of photos, “Beach Stones” (2006), Margaret Carruthers observes:
A beach is a strip of loose material at the water’s edge, a collection of sand and stones assembled, disassembled, and reassembled by the sea. On the geologic time scale, it is ephemeral. And for most stones, the beach is just the latest stop on a journey that began eons ago. (page 7)
For these 30 stones, the next stop on their journey lies across a great ocean and a great continent.
DELIVERY UP-DATE: I posted the stones on 1 December 2020. Sheila sent me a photo on 23 December (NZ time) showing they had been delivered! (It’s winter there, summer here.)
POSTSCRIPT: Sheila kindly sent me a delightful book on New England’s stone walls – thank you!
Great series. Thankyou for posting
Thank you for the feedback, John.
i found a stone that baffled me at st andrews. Like yours from kakanui. green with the spots. These are slightly raised. If you know what it is now i am keen to know.