xii Birds of Colorado 



Physical Features of Colorado. 



The State of Colorado lies near the centre of the United 

 States, about two-thirds of the distance from the Atlantic 

 to the Pacific coasts. It is quadrilateral in shape, measur- 

 ing about 276 miles from north to south, and about 375 

 from east to west. It has an area of about 103,900 

 square miles. 



In general terms, the eastern third of the State consists 

 of open, bare, dry plains, where the country is flat or 

 rolling, and where there is hardly any timber except 

 along the river bottoms. The elevation of these plains 

 (the prairies) rises from about 3,500 feet at the Kansas 

 border to 6,000 feet at the foothills of the Rocky 

 Mountains. 



West of the 105th meridian, and rising with extra- 

 ordinary abruptness from the plains to the east, the 

 Rocky Mountains occupy roughly the middle third of 

 the State. In a very general way the system forms 

 two parallel ranges running north and south, joined by 

 subsidiary east and west connections ; between these 

 are the great mountain parks, open wide valleys rather 

 bare of trees, and situated at elevations of 7,000 to 

 8,000 feet. 



The chief of these are North and South Parks, drained 

 by the North and South Platte rivers, which meet out in 

 the plains of Nebraska and join the Missouri near Omaha ; 

 Middle Park, drained by the Grand River, the principal 

 affluent of the Colorado River of the west, draining into 

 the Gulf of CaHfomia ; and the San Luis VaUey, draining 

 into the Rio Grande on the south. 



The western third of the State consists, to a large 

 extent, of a series of descending plateaus through which 

 the rivers, all tributaries of the Colorado, have cut canons 



