1903.] Gidley, Fresh-water Tertiary of Northwestern Texas. 633 



exposures, however, show an extensive distribution to the 

 northeast. 



Here again, as at Tule Canon and Mount Blanco, the pecu- 

 liar formation of the deposits indicates, though in a somewhat 

 different manner, an alluvial origin. Though distributed over 

 a wider area in every direction there are running through these 

 beds several narrow channels of sandy clay. The main body of 

 the beds consists for the most part of cross-bedded sands and 

 sandstones intermixing more or less and cross-bedding with 

 the clays. These channels all take a direction nearly east and 

 west, or approximately the same as that of the streams drain- 

 ing the country at the present time. Some of them are trace- 

 able for long distances. It is in these peculiar beds of sandy 

 clays that all the fossils of this region occur. 



Cummins's section of the Clarendon locality is as follows: 



1. Whitish sandy clay 20 feet 



2. Sandy clay, with many rounded siliceous pebbles of differ- 



ent sizes 20 



3. Yellowish sand 40 



4. Indurated white sand 40 



5. Yellow sandy clay, with the sand more or less predominat- 



ing in places. In places the sand is hardened, while in 

 others the clay is more or less concretionary 250 



6. Alternating beds of bluish clay and white sand (Loup 



Fork) 30 " 



400 feet 



Cummins has here placed the Loup Fork formation at the 

 very bottom of this section of 400 feet of deposits. A careful 

 study of this region, however, does not warrant such a dis- 

 position of this stratum. In reaHty this stratum (No. 6) 

 belongs properly at the top of the above section, and the 

 explanation is simple. Nowhere is bed No. 6 overlaid by 

 any of the upper strata of the section; hence to obtain this 

 section Cummins probably included the beds west to the top 

 of the plains, and because No. 6 was at a lower level concluded 

 that it ran under the beds to the west. This, however, is 

 erroneous. The writer found several places where this fossil- 

 bearing stratum lies unconformably on the eroded surface of 



