the sea with thundering noise creating a boiling like turbulence. The Glacier Bay was closed for ships almost a decade after the 1899 earthquake (magnitude 8.4 on the Richter Scale). This was on account of the shattered ice blocks which filled the Bay consequent to the earthquake. Even though the Bay is in volcanic activity region of the Pacific "Rim of Fire", active volcanoes have not been recorded within the Glacier Bay Basin. However, these two factors have been inferred to have effects on the environmental changes occurring in the Glacier Bay. Archeological findings Archaeological findings have been unearthed at two sites in the Glacier Bay, which links the region to Holocene period. On the Baranoff Island, a prehistoric finding dates occupation of the region between 3200 and 4600 BP. Another finding in the form of a house, microlithic tools and heavy wood working tools at Ground Hog Bay has been dated to about 2000 BP. This is stated to be "towards the end of the Hypsithermal (thermal maximum climatic fluctuation) and the beginning of the Little Ice Age". Thus, it has been interpreted by comparison with similarly placed locations in the region, such as the southern coast of British Columbia, that the type of culture seen here is comparable to the culture that existed during historic times on the Northwest Coast. The potential for finding more such sites are stated to be high. Ethnographic aspects The Tlingits regard Glacier Bay as their sacred homeland. The National Park Service takes the view that "Glacier Bay National Park is the spiritual homeland of the Huna Tlingit, and Glacier Bay National Preserve is the homeland of the Ghunaaxhoo Kwaan unit of the Yakutat Tlingit Tribe". The tribes' oral history supports that they were pushed out and migrated south when the glacier advanced. They moved back to the area when the Glacier retreated in the 1880s. There are 60 odd proto-historic or historic sites in the Glacier Bay, which are identified with Tlingit Indians or European Americans. They are an integral part of Northwest Coast people inferred to be belonging to Haida, Tlingit or Eyak clans. Their settlements existed even in the 1880s in Dry Bay, Excursion Inlet, Point Couverden and the Port Frederick area (now known as Hoonah) and Dundas Bay. A Tlingit cemetery of the period has also been located in the park area. Seasonal hunting, gathering and fishing was their