This was once a bear, but not like any bear in North America today. Claw marks gouged into the cave wall showed the bear was not killed direct by the fall. It made a desperate attempt to climb back out. It was a short-faced bear, an ice age heavyweight. What else can we tell about it from its bones? Its weight was more than 700 kilos, twice that of a grizzly bear today. Upright, it would’ve stood four meters tall. It was the largest flesh-eating mammal that ever walked the earth.
The Wyoming cave, appropriately christened natural trap, provides a unique window of the Ice Age. During its coldest era, much of North America was covered by huge ice sheets up to two miles thick, but as the continent began to warm, the ice sheets started shrinking.
Corridors began to open up along the coast and through the mountains, letting people migrate south from Alaska for the first time. Before them lay the almost limitless great plains stretching all the way from the Rocky Mountains to the Mississippi River and beyond to Mexico.
Across this area, the shifting ice left deep scars on the land. They carved out thousands of lakes and ponds, and left the tapestry of streams and rivers that drained the plains.
1 gouged
v.凿( gouge的过去式和过去分词 );乱要价;(在…中)抠出…;挖出…
参考例句：
The lion's claws had gouged a wound in the horse's side. 狮爪在马身一侧抓了一道深口。
The lovers gouged out their names on the tree. 情人们把他们的名字刻在树上。 来自《现代英汉综合大词典》
2 grizzly
adj.略为灰色的，呈灰色的;n.灰色大熊
参考例句：
This grizzly liked people.这只灰熊却喜欢人。
Grizzly bears are not generally social creatures.一般说来，灰熊不是社交型动物。
3 tapestry
n.挂毯，丰富多采的画面
参考例句：
How about this artistic tapestry and this cloisonne vase?这件艺术挂毯和这个景泰蓝花瓶怎么样?
The wall of my living room was hung with a tapestry.我的起居室的墙上挂着一块壁毯。
