ABSTRACTS OF PAPERS 123 



tions representing a large area. The oldest formation seen was the Goodridge, 

 of Pennsylvanian age. Shales overlying the Goodridge formation along San 

 Juan River are believed to correspond to the Hermit shale of the Grand 

 Canyon section. These shales are in turn overlain by cross-bedded sandstone, 

 at least 1,000 feet thick, which forms the walls of Cataract Canyon on Colo- 

 rado River. Apparently this sandstone, which is overlain unconformably by 

 the Moenkopie formation, occupies the place of the Coconino sandstone and the 

 Kaibab limestone of the Grand Canyon section. The Moenkopie formation 

 thins and becomes sandy toward the north. The De Chelly sandstone is evi- 

 dently an irregular lentil wedging into the Moenkopie. The Shinarump con- 

 glomerate, with all its characteristic features, is present in the area, but it 

 becomes discontinuous toward the north. Many features of the Chinle and 

 La Plata formations were noted for comparison with sections in other areas. 

 Structural and physiographic features were also studied. 



Presented in full by C. E. Longwell without notes, with lantern-slide 

 illustration. 



Remarks were made by W. M. Davis and David White. 



Discussion 



Mr. David White : It is appropriate here to call attention to the correlations 

 recently made of the De Chelly with the Coconino by Mr. Darrey Hogu in a 

 very recently published paper on "Oil possibilities of the Holbrook area in 

 Arizona." In autographically corrected copies received from Mr. Hogu, the 

 former correlation by him of the La Plata with, the De Chelly is rescinded and 

 the De Chelly is made equivalent to the Coconino, the upper Goodridge of the 

 San Juan area being attached to the Supai. The Moenkopie of Woodruff and 

 Gregory, in the San Juan region, he places with the Supai. This record is 

 submitted at Mr. Hogu's request. 



CAMBRIAN SUCCESSION OF NORTHWESTERN VERMONT 

 BY ARTHUR KEITH 



(Abstract) 



The Champlain Valley, in northwestern Vermont, afforded for years the 

 type section of the Lower Cambrian, and the town of Georgia gave its name 

 to the series. This series, or group, is divided in this paper into ten formations 

 of quartzite, dolomite, limestone, and marble. Four formations of later Cam- 

 brian and eight of Ordovician age are also recognized, including sandstone, 

 dolomite, limestone, marble, and slate. Numerous new localities for fossils 

 are described. The term Georgia is shown to have no longer a large taxo- 

 nomic value. 



Conglomerates, mainly basal, are described at six horizons ; three of them are 

 of major importance and follow long erosion intervals. Two great overlaps are 

 recorded. The formations fall into three groups or sequences, formed under 

 different environments, and now crowded into contact by great overthrusts. 

 One great deformation took place in the late Precambrian and was followed 



