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Show RELATIONS OF HIGH PLATEAUS TO PLATEAU PEOVINCE. 9 now, and every branch and every twig of a stream runs in cations. The land is thoroughly dissected by them, and in many large tracts so intricate is the labyrinth and so inaccessible are their walls, that to cross such regions except in specified ways is a feat reserved exclusively to creatures endowed with wings. The region at levels below 7,000 feet is a desert. A few miserable streams meander through it in profound abysses. The surface springs will not average one in a thousand square miles, for the canons in their lowest depths absorb the subterranean water-courses. But in the High Plateaus above we find a moist climate with an exuberant vegetation and many sparkling streams. « EELATIOKS OF THE HIGH PLATEAUS TO THE PLATEAU PROVINCE AT LARGE. It is impossible to gain any adequate conception of the broader and more general features of the High Plateaus apart from their relations to the Plateau Province at large. The geological history of the district is inseparable from that of the province of which it is a part, and that history is full of interest and instruction. Beyond Cretaceous time it is unfortunately vague and uncertain at present; and even during the Cretaceous our knowledge is limited as yet to a few salient facts too conspicuous to be overlooked, but of very great geological importance. We now know that during Cretaceous time the ocean stretched from' the Wasatch to Eastern Kansas, Nebraska, and Dakota, and from the Gulf of Mexico far northwards toward the Arctic Circle. The area now occupied by the Great Basin was then a large island, or possibly a portion of some unknown continental mass. East of it probably lay numerous islands. Around the southern border of this area the Cretaceous ocean joined the Pacific, covering the entire extent of the Plateau Province and more to the southwestward. We find throughout the plateaus vast bodies of Cretaceous stata which seem in a general way or collectively to correspond with those which have been studied and described by Meek and Hay den in the Great Plains of Nebraska, Dakota, Montana, Wyoming and Colorado, and by Newberry in New Mexico and Arizona. Although the subdivisions of the Plateau Province have not been wholly correlated with the marine Cretaceous of the other territories north and east, there can be little doubt that the series as a whole agrees in general. The lower |
