Geological Papers. 87 



come more and more pronounced, until from six miles or more 

 north it makes a much more prominent escarpment than the Cot- 

 tonwood limestone. The appearance of the Cottonwood limestone 

 on the escarpment, where it may be seen, is nodular, shelly and 

 shaly-looking (not distinctly shaly, but weathering somewhat that 

 way). An examination at the point above mentioned shows the 

 Cottonwood limestone, which can be seen only in places, to be 

 about two feet thick, bluish in color, breaking up into flagging 

 nodules without seams, FusuUiia occurring. The Florena shales 

 can be well observed here, containing the characteristic fossils, this 

 being an excellent place for collecting. The limestone overlying 

 the Florena shales measured fourteen feet in thickness and consists 

 of a fossiliferous layer containing Fusuli7ia, crinoid stems and 

 many molluscan shells, weathering into the appearance of flagging, 

 the thickness of which is two feet, the lower ten or twelve inches 

 being fossiliferous. Above this part the limestone appears in lay- 

 ers of yellow lime, easily eroded, containing soft layers, causing the 

 weathered appearance to be that of massive blocks. This massive 

 layer is- fully nine feet thick at this place. Some of the layers 

 weather into jagged, knotty, irony lime, which appear on the out- 

 crop. No fossils were found in any but the lower layers. 



A layer of clay occurs just above this limestone for several miles 

 and causes many springs, giving it the appearance of springs almost 

 on top of the hill, and the ravines are very rugged. In the main 

 there are two massive layers of this limestone, with a more or less 

 easily eroded layer between them, the lower layer weathering into 

 jagged, honeycombed rock, which appears on the outcrop. A few 

 feet below the Cottonwood limestone a bluish-looking lime of one 

 and a half feet in thickness continues, this being the limestone that 

 has taken the place of the calcareous shale further north. 



On the Santa Fe railroad, west of Grenola and for many miles 

 to the north, the lime above the Florena shale makes a very promi- 

 nent mesa. The Cottonwood limestone makes a very inconspicu- 

 ous one, which is continuous, but is usually the same as a small 

 step just below the prominent one. The outcrop of the Cotton- 

 wood limestone appears nodular; the shale above it is more con- 

 spicuous than the limestone. Many small ravines in it afford 

 excellent opportunity for observing its characteristic fauna, which 

 occur in great abundance. The railroad cut about a half mile east 

 of Grand Summit, at the top of the hill, is mostly in the shale 

 above the lime which is above the Florena shale. The cut and 

 quarry in this limestone afford an excellent opportunity for study- 

 ing it. This limestone appears columnar on the outcrop. On ex- 



