A mysterious orange substance that washed up on the shores of an Alaskan village last week was a mass of microscopic, invertebrate eggs, possibly those of a small crustacean, a National Oceanic and Atmospheric Administration lab said Monday.

More testing will determine the species and whether the eggs - whose appearance on the shores of Kivalina in northwest Alaska startled residents Wednesday - are toxic, said Julie Speegle, representative of the NOAA Alaska Fisheries Science Center's Auke Bay Laboratories.

Residents of Kivalina, an Inupiat Eskimo village of about 430 people, found the substance in its lagoon - giving the lagoon an orange sheen - and clumps of the orange stuff on the beach. A resident who took pictures of the substance, Mida Swan, said last week that it had an oily feel, like baby oil.