Fossils can be used to match up rock layers. As organisms change over time, they look different. Older fossils will look different than younger fossils. Some organisms only survived for a short time before going extinct. Knowing what organisms looked like at certain times also helps date rock layers. Some fossils are better than others for this use. The fossils that are very distinct at certain times of Earths history are called index fossils. Index fossils are commonly used to match rock layers. You can see how this works in Figure 2.30. If two rock layers have the same index fossils, then they're probably about the same age.

How can extinction help to date rock layers?

Grande dame of cooking still going strong at 90: Julia Child celebrates in San Francisco. How does it feel to turn 90 and have attained the status of an icon, a living legend? "It feels just like it felt before," Julia Child says with the throaty laugh familiar to millions who cut their culinary teeth on her "French Chef" television series. The show, along with her seminal book, "Mastering the Art of French Cooking" (1961), revolutionized the way America cooks and eats. While making light of the difference a day -- or another decade -- makes, Child intends to enjoy her birthday thoroughly. First, there will be all the public observances, including a sold-out dinner Thursday at San Francisco's tony Fifth Floor restaurant, which -- like dinners that night at 19 other venues across the country -- will benefit the scholarship fund of the International Association of Culinary Professionals (which Child co-founded). Friday to Sunday, the action moves to Napa, with both members-only and public events at COPIA: The American Center for Wine, Food and the Arts, of which she is an honorary board member. Aug. 15, her actual birthday, will see her in Maine at an annual gathering of nieces, nephews, their offspring and friends, who for many years have rolled a joined birthday celebration for several members of the group into a jolly reunion. The schedule Child and her assistant of 14 years, former pastry chef Stephanie Hersh, have laid out is not exactly a senior-citizen routine, even though Child has always been candid about her age and realistic in assessing her own capabilities. When the Pasadena native moved back to California from her long-time home in the Boston area last year, she also made the move from a condominium she and her late husband, Paul, had purchased many years ago to a progressive retirement home. She is in the most active of the four levels available, but should the need arise, she can move on to assisted living facilities within the same complex.

What two popular accomplishments did Julia Child revolutionize the way American's eat?

Mr. Neville ( ( ( Anthony Higgins , a young and arrogant artist and something of a Byronic hero , is contracted to produce a series of 12 landscape drawings of an estate by Mrs. Virginia Herbert for her absent and estranged husband . Part of the contract is that Mrs. Herbert agrees '' to meet Mr. Neville in private and to comply with his requests concerning his pleasure with me . '' Several sexual encounters between them follow , each of them acted in such a way as to emphasise reluctance or distress on the part of Mrs Herbert and sexual aggression or insensitivity on the part of Mr Neville . Meanwhile , whilst living on the estate , Mr. Neville gains quite a reputation with its dwellers , especially with Mrs. Herbert's son-in-law , Mr. Talmann . Mrs. Herbert , wearied of meeting Mr. Neville for his pleasure , tries to terminate the contract before all of the drawings are completed and orders Mr. Neville to stop . But he refuses to void the contract and continues as before . Then Mrs. Herbert's married , but as yet childless , daughter , Mrs. Talmann , who has apparently become attracted to Mr. Neville , seems to blackmail him into making a second contract in Which he agrees to comply with what is described as her pleasure , rather than his a reversal of the position in regard to her mother . A number of curious objects appear in Neville's drawings , Which point ultimately to the murder of Mr. Herbert , whose body is discovered in the moat of the house . Mr. Neville completes his twelve drawings and leaves the house .
Why did Mrs. Herbert want to cancel the contract between her and Mr. Neville?