To me it looks a bit like a wet and worn out bitumen road after heavy rain.
Most streets built before the early 1900s in NZ were made of macadam, which was highly suitable for horse-drawn vehicles. However, with the rise of motor traffic in the 1920s, many areas had to seek more durable options for road surfacing. The most frequently used material became asphalt or bitumen, which gained widespread use starting in the 1920s.
I think you're probably right. The wibbly-wobbly-ness of it makes it look like the surface of water, though admittedly on my computer rather than my phone it looks a lot more like a wet road. I'd guess the wobbly nature of the surface is partly due to wear as you say, but also I presume road building techniques have come a long way in the last 100 years.
Yeah. On my phone it looks also more like water than just a wet road.
... but also I presume road building techniques have come a long way in the last 100 years.
That's what I find so fascinating about old photos. You can see how quickly technology has developed in 100 years. And the development is progressing faster and faster every year.
On the right side there are power lines but I am not sure if the thin cables on the left are power lines. They are very thin. Maybe phone lines or telegraph cables.