Newly discovered dinosaur tracks
A cluster of dinosaur tracks discovered recently in Alaska has revealed to paleontologists a wealth of new information about their behavior.
The thousands of impressions, created on a 180-meter-long portion of near-coastal flood plain, today pepper a steep mountainside. Most of the tracks, made somewhere between 69 million and 72 million years ago, were left by hadrosaurs, commonly known as duck-billed dinosaurs (the crested creatures in this artist’s representation).
The consistent and excellent preservation of tracks suggests all the footprints were created within a short time period. Varying in width from 8 to 64 centimeters, the footprints cluster within four distinct size ranges, which researchers suggest represent specific age groups within a multigenerational herd. About 84% of the tracks were made by adult and near-adult hadrosaurs and 13% by young presumed to be less than 1 year old. A mere 3% of the tracks represent juvenile hadrosaurs, a rarity that strongly suggests the young of this species experienced a rapid growth spurt and therefore spent only a short time at this vulnerable size, the researchers report online this week in Geology.
On Christmas Eve 1968 three Americans became the first humans to visit another world. What they did to celebrate was unexpected and profound, and will be remembered throughout all human history. Genesis: the Story of Apollo 8, Robert Zimmerman's classic history of humanity's first journey to another world, tells that story, and it is now available as both an ebook and an audiobook, both with a foreword by Valerie Anders and a new introduction by Robert Zimmerman.
The ebook is available everywhere for $5.99 (before discount) at amazon, or direct from my ebook publisher, ebookit. If you buy it from ebookit you don't support the big tech companies and the author gets a bigger cut much sooner.
The audiobook is also available at all these vendors, and is also free with a 30-day trial membership to Audible.
"Not simply about one mission, [Genesis] is also the history of America's quest for the moon... Zimmerman has done a masterful job of tying disparate events together into a solid account of one of America's greatest human triumphs."--San Antonio Express-News
A cluster of dinosaur tracks discovered recently in Alaska has revealed to paleontologists a wealth of new information about their behavior.
The thousands of impressions, created on a 180-meter-long portion of near-coastal flood plain, today pepper a steep mountainside. Most of the tracks, made somewhere between 69 million and 72 million years ago, were left by hadrosaurs, commonly known as duck-billed dinosaurs (the crested creatures in this artist’s representation).
The consistent and excellent preservation of tracks suggests all the footprints were created within a short time period. Varying in width from 8 to 64 centimeters, the footprints cluster within four distinct size ranges, which researchers suggest represent specific age groups within a multigenerational herd. About 84% of the tracks were made by adult and near-adult hadrosaurs and 13% by young presumed to be less than 1 year old. A mere 3% of the tracks represent juvenile hadrosaurs, a rarity that strongly suggests the young of this species experienced a rapid growth spurt and therefore spent only a short time at this vulnerable size, the researchers report online this week in Geology.
On Christmas Eve 1968 three Americans became the first humans to visit another world. What they did to celebrate was unexpected and profound, and will be remembered throughout all human history. Genesis: the Story of Apollo 8, Robert Zimmerman's classic history of humanity's first journey to another world, tells that story, and it is now available as both an ebook and an audiobook, both with a foreword by Valerie Anders and a new introduction by Robert Zimmerman.
The ebook is available everywhere for $5.99 (before discount) at amazon, or direct from my ebook publisher, ebookit. If you buy it from ebookit you don't support the big tech companies and the author gets a bigger cut much sooner.
The audiobook is also available at all these vendors, and is also free with a 30-day trial membership to Audible.
"Not simply about one mission, [Genesis] is also the history of America's quest for the moon... Zimmerman has done a masterful job of tying disparate events together into a solid account of one of America's greatest human triumphs."--San Antonio Express-News
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