Island 35 Mastodon Island 35 Mastodon The Island 35 Mastodon was discovered on Island No. 35 of the Mississippi River in Tipton County, Tennessee, United States. In 1900, a Pleistocene mastodon skeleton was excavated approximately east of Reverie, Tennessee and southeast of Wilson, Arkansas. In 1957 the site was reported as destroyed. Mastodons are members of the prehistoric, extinct genus "Mammut". They resemble modern elephants. Native to North America, they are said to have lived on the North American continent from almost 4 million years ago, in the Pliocene Epoch, until their eventual disappearance about 10,000 years ago. In 1900, archaeologist James K.
Extinct comet the Hubble search for transition comets. Comets such as C/2001 OG108 (LONEOS) may represent the transition between extinct comets and typical Halley-type comets (periods of 20–200 years) or long period comets (periods longer than 200 years). Minor planets of the group of damocloids have been studied as possible extinct cometary candidates due to the similarity of their orbital parameters with those of Halley-type comets. Dormant comets are those within which volatiles may be sealed, but which have inactive surfaces. For example, 14827 Hypnos may be the nucleus of an extinct comet that is covered by a crust several centimeters thick