Dark Periwinkles

Thanks to the Australian Museum in Sydney, I've been able to identify this spotting. These are dark periwinkles, a native species of mollusc that's endemic to this area. Size up to 7 mm in length, but commonly 2-3 mm. This spotting shows them in juvenile form, and they are tiny! Mass aggregations like this are to conserve moisture, seen here with Austrolittorina unifasciata, aka little blue periwinkles.... https://www.projectnoah.org/spottings/1970239271. "The colour is variable from dark brown to pale fawn, and from unpatterned to strongly marked. The colour is usually dark brown in the early whorls - hence juvenile shells are dark brown - changing to fawn or light brown on the latter whorls. Shells may be translucent, particularly the lighter coloured specimens." (Seashells of NSW) https://seashellsofnsw.org.au/Littorinidae/Pages/Afrolittorina_acutispi…