4mm red band across it, the other with two. Frederickson was unable to find similar specimens elsewhere in central California, but did note similarities with pebbles excavated near Los Angeles. Comparison with other similar painted stones and shells suggested that they might have been used as gaming pieces or dice, or that the two designs might have been intended to symbolize male and female elements. Coles's research showed that the use of the island was stable over a long period, but not whether occupation there was year-round or seasonal. Kent Lightfoot of UC Berkeley is reanalyzing Coles's material to determine whether seasonal patterns can be identified. The latest carbon-14 date from the shellmound material is about 300 years ago, but it is possible that the island was used until the era of European contact. The Richmond Museum of History acquired Coles's collection of Brooks Island artifacts following his death in 2015. Early European period Juan Manuel de Ayala conducted the first nautical survey of San Francisco Bay in 1775 and named the island Isla de Cármen. In the early 19th century, while California was a Spanish colony, it became part of Rancho San Pablo. However, Spanish records from that period do not mention any settlement on the island. By 1850, the island appears as "Brooks Island" on an 1850 survey map of the San Francisco Bay area made by Cadwalader Ringgold, a name that was formalized in the state legislature's definitive map of California in 1853. However, no record has been found as to which Brooks the island was named for. During the 19th century the island was also called Sheep Island. One apocryphal story relates how a Croatian immigrant named Luccas Gargurevich who settled on the island in 1870 told his son Anton that "The man on Goat Island raised sheep, and I raised goats, so I have named it Sheep Island." Despite this, Gargurevich seems unlikely to be the source for this alternative name as Sheep Island appears on an 1856 map. In 1880, Gargurevich was joined on the island by his new wife Dominica, and they had nine children while living there. To educate them, he built a schoolroom and hired a teacher who traveled from Oakland. After Dominica died in childbirth, Luccas and his children left the island. Today, only a stone wall remains from the buildings of this period. As well as using the island