07/26/2021

Three-toed, dog-size horses; four-tusked elephants; and barrel-bodied rhinos are just some of the creatures that dotted the grasslands of Nebraska 12 million years ago, revealed in this accessible nonfiction tome by Stevens. Drawn to a seasonal water hole, the animals became fossilized after a supervolcano erupted and covered the landscape in ash, remaining undisturbed until 1953, when a rhino skull was found, and then the 1970s, when geologists revisited the Ashfall Fossil Beds. Stevens skillfully narrates the journey dozens of scientists undertook to excavate, identify, and preserve the fossils, unpacking concepts in simple prose, as in this explanation of modern horses’ lack of three toes: “Growing toes (or any other body part) takes energy. When animals no longer need the body part, it often gets smaller or disappears completely.... It’s a slow process that takes place over many generations.” B&w photographs and folk art–style brush-and-ink illustrations by Huynh lend atmosphere. The book’s second half, describing the less dramatic scientific work of ground-penetrating radar and electron microscopes, feels perhaps overly long, but this is an intriguing primer on lesser-known paleontological subjects. Back matter includes a glossary, author’s note, and resources. Ages 8–12. (July)

07/01/2021

Gr 5 Up—This title explores the surprising discoveries made at Nebraska's Ashfall Fossil Beds over a 50-year span, including information about new species, geological events, and animal behavior. At the same time, Stevens provides fascinating insights into the techniques scientists use to reconstruct the ancient past. The writing is lively, clear, and sometimes conversational. Fluid nonfiction storytelling presents the research in terms of mysteries to be solved, and readers gain an increasingly fuller picture of the work and its results with each new revelation. The author does a nice job of introducing material, then building upon it in subsequent chapters. The process of pinpointing the dates of the fossils, for example, involves three different methods over time, each one further solidifying theories. Explanations of key concepts such as evolution or fission tracks are clear and supported neatly by examples. The logistics of this huge, multiyear project emerge in different ways, such as the careful methods used to avoid damaging specimens and the need to bring in experts in various fields to uncover the full truth. Short, well-organized chapters help to break up the wealth of information into sections without overwhelming readers. The chronologically arranged narrative conveys the passage of several decades, but dates are usually not provided for specific events. Visual support is provided with black-and-white drawings of the ancient creatures, along with occasional diagrams and photographs of fossils. VERDICT Engaging science content for older readers who love paleontology.—Steven Engelfried, Wilsonville P.L., OR

2021-05-19
Scientific investigation of a quarry in Nebraska reveals that 12 million years ago it was a very different world.

Science writer Stevens describes the process of finding and identifying a treasure trove of extinct animals—full skeletons—buried in volcanic ash from an eruption in today’s Idaho. There were rhinos, horses, camels, saber-toothed deer, birds, turtles, and even bone-crushing beardogs. She recounts the ways scientists have worked together and separately since 1953 to excavate specimens, date ash layers, deduce animal behavior, figure out their environment, and identify the volcano. Poison Ivy Quarry became Ashfall Fossil Beds State Historical Park, where fossils continue to be revealed but are left in place; visitors can observe the ongoing research. Realistically, she includes some of the hiccups and dead ends. She introduces scientists, interns, and students from various fields. Her clear exposition includes examples of the clues that inform their deductions about the animals and their environment, helping readers understand how these researchers arrive at their conclusions. She explains less-familiar techniques, concepts, and equipment such as topographic maps, radioactive dating, convergent evolution, scanning electron microscopes, plate tectonics, and ground-penetrating radar. Specialized vocabulary is printed in boldface and defined both in context and in a glossary. Huynh’s brush-and-ink paintings are an inspired addition to this account of the work of re-creating a long-distant history; there are also helpful black-and-white photographs.

Welcome evidence that paleontology is about more than dinosaurs. (author’s note, resources, acknowledgments) (Nonfiction. 9-14)