Inhaltsangabe
This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1876. Excerpt: ... The character of the subdivisions will be better seen by the following analysis: 1st. Yellow sandstone group; here less coarse and containing less conglomerate than at camps 33, 34, and 35. As at those localities, on the Cimarron, in Kansas and Nebraska a portion of this group is here an exceedingly hard, whitish, quartzose sandstone. Beds of lignite and silicified wood are common. 2d. Greenish shales and sandstones; the same group described in my notes on the geology of the vicinity of Camp 34, Nos. 10, 11, 12 of section, page 104, here much less highly colored, consisting of thick beds of greenish shale, locally pink or purple, with bands of yellowish, greenish or purple concretionary silicious rock; no fossils. 3d. Greenish sandstones and shales; the same group exposed in the lower part of the section at Camp 34. The shales and sandstones frequently replace each other; the group at Camp 37 being nearly all massive, yellowish-green sandstone, while, a few miles below, the shales greatly predominate; no fossils discoverable. "Mouth of the Mancos.--Camp 38, thirteen miles. We have to-day ascended in the geological scale, have nearly submerged the lowest member of the section at Camp 37, and the mesas back from the river on the north side run far up into the Middle and Upper Cretaceous group. On the south side the mesas are not as high; the Lower Cretaceous rocks forming the surface almost to the Sierra Carrizo, near which the Upper Cretaceous beds appear again. The mesas north of our camp, composed of the Middle Cretaceous strata,extend north and east to the base of the Sierra Le Late, and, if not cut off by the valley of the Mancos, would connect with the Mesa Verde. As usual in all this region, the shales contain great numbers of Gryphcea Pitcheri. "In ...
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