498 H. B. PATTOX CARLILE SHALE AND TIMPAS LIMESTONE 



The above described characteristics are well shown at the base of the 

 cliff on the south side of Horse Creek, in the northeast quarter of section 

 30, township 23 south, range 53 west, and they continue for 5 or 6 miles 

 northeast of this point, which is as far as the field-work wa^ carried. 



Figure 2. — Contact of Timpas Limestone and Carlile Shale 



The contact occui*s in Anderson Arroyo, about 7 miles south of La Junta. The pho- 

 tograph shows the soft black shale at bottom, the 3-foot brown limestone that marks 

 the top of the Carlile shale in the middle, and the white, basal Timpas limestone at 

 the top. 



Carlile Fossil ix the Timpas Limestone 



In line with the observed merging of these two limestone members at 

 the top of the Carlile and the bottom of the Timpas is the discovery of a 

 recognized characteristic Benton fossil in the basal limestone of the 

 Timpas. Xear the center of the east half of section 27, township 22 

 south, range 53 west, and about 3 miles east of the location above given, 

 a specimen of Inoceramus was collected near the base of the Timpas 

 limestone. This fossil has been identified bv Prof. Junius Henderson, 

 of the University of Colorado, as Inoceramus Idbiatm, a form considered 

 characteristic of the Benton group and very common in the Greenhorn 

 limestone member of that group. 



We have here, then, a case of a sandstone member thinning out toward 

 the east and passing into a cryst-alline limestone, and the eventual merg- 

 ing of that limestone into the basal limestone member of a higher group. 

 We also have, associated therewith, the passing of a typical fossil of the 

 lower group up into the higher group. 



