Mancos 



SECTION OF CRETACEOUS ROCKS 589 



Feet In. Feet In. 

 Shale with trausitional beds of thin sand- 

 stone and shale at the top, containing 

 j Qryphcea newherryl Stanton, 60 feet above 



[ the base, 1,200 to 2,000 feet thick 1,600± 



],G00± 



Dakota and 



sandstones at 



base of 



Mancos 



Sandstone, massive, gray, qnartzose 20 



Shale, dark and gray, with local thin coal 



beds and some shaly sandstone 40 



Sandstone, massive, gray, qnartzose 50 



Shale and thin sandstone with local car- 

 bonaceous layers and thin coal beds 100 



Sandstone, massive, gray, quartzose 15 



225 



Total 9,G98 11 



In order to correlate the formations described from central New 

 Mexico with those of the Durango region, the writer made a somewhat 

 hasty trip to Durango, w^here the Cretaceous formations are well exposed 

 along the Animas Eiver. Careful search was made for fossils in the 

 Mesaverde, Lewis, and "Laramie." None were found in the Lewis, and 

 the Mesaverde was found to be barren in many places, although a few 

 shells and poorly preserved fossil leaves were found in it. Half a mile 

 west of Twin Buttes, at the mouth of the gulch, entering Lightner Creek 

 from the west, several fossil plants were found, but most of them are too 

 poorly preserved to be specifically identified. They are Equisetum sp., 

 Sequoia reichenbachi (Gein.) Heer, Fern, Quercus sp., Quercus n. sp.. 

 Palm, and Ficus sp. (United States Geological Survey, locality No. 

 6043). In this gulch, half a mile farther west, Baculites anceps var. 

 obtusus Meek was found above the main coal beds. A single palm, 

 Geonomites sp., very similar if not identical with a species common in 

 the lowest coal formation of the Raton coal field, was found on the dump 

 of an old mine in the Mesaverde coal, which opens in the gulch about 1 

 mile south of the Durango smelter, and on the dump of another mine in 

 Horse Gulch, in the same coal measures, about half a mile east of Du- 

 rango, Ficus lanceolata Heer and Ficus sp. were found. The fossil leaves 

 seemed to be confined to very restricted zones closely associated with the 

 coal. Baculites anceps var. obtusus Meek was found in the Mesaverde 

 above the coal in several places near Durango. Such limited observa- 

 tions as were made in this region gave the impression that the Mesaverde 

 is here essentially a marine formation. This observation seems to be 

 verified by the work of other geologists. Fossils collected from this for- 

 mation several years ago and identified by Doctor Stanton are as follows : 



