HORIZON OF THE MARINE JURASSIC OF UTAH 645 



4. That portion of the Flaming Gorge described by Emery as 

 the Navajo is lithologically very unlike the type Navajo. Among 

 these dissimilarities may be mentioned the presence of much shale 

 and considerable gypsum in the Navajo as described by Emery, 

 and their conspicuous absence in the Navajo of Gregory. Further- 

 more, Gregory describes much limestone as an almost universal 

 characteristic near the top of the Navajo sandstone in its type 

 region. The Navajo of Emery is apparently quite without such 

 limestones. 



5. According to Gregory, greenish tints prevail in the base of 

 the McElmo. The basal part of the section measured by the 

 writer also shows many greenish beds. 



6. In the section measured by the writer, totahng 989 feet, in 

 which only the lower 165 feet are clearly La Plata, there are 824 

 feet of beds, among which it is almost impossible to draw any 

 boundary. They are certainly not all Todilto, or else the Todilto 

 has thickened most enormously in this section. If they are in part 

 Navajo, as must be the case, under Emery's conclusion, then the 

 Navajo here grades inseparably into Todilto. 



7. The McElmo, in Gregory's report, is described as extremely 

 variable, but as prevailing sandy, with many intricately cross- 

 bedded sandstone members, a description which fits well the 

 characteristics of the supposed Navajo of Emery's paper. 



8. If the basal part of the Flaming Gorge be considered as 

 Todilto and Navajo, the total thickness of the La Plata group in 

 the Water Pocket Canyon region will approximate 2,500 feet, 

 which represents at least unusual thickening of the formation. 



9. The old original classification by Gilbert represents a group 

 of lithologic units with much more natural physical boundaries, 

 at least in the area studied by the writer, than do those presented 

 by Emery. In justice it must be said, however, that the writer has 

 not seen the localities described in Emery's paper. His own 

 section was measured about midway between the area studied by 

 Emery and the Water Pocket Canyon, and he has studied the 

 formations south but not north of that point. 



ID. The gypsiferous beds of northern New Mexico, so frequently 

 mentioned by Lee, do not appear to be overlain by any beds that 



