MOOK, STUDY OF THE MORRISON FORMATION 63 



The formation was traced by Lee eastward from Folsom to a point 

 seven miles east of the boundary between New Mexico and Oklahoma. 

 The formation is made up, as usual, of variegated clays with minor 

 amounts of sandstone and limestone. "All the members of this forma- 

 tion vary laterally in character and thickness. No two sections exhibit 

 the same order of succession nor the same relative proportion of mate- 

 rials" (Lee, 1902, 5). One member which is persistent in this area is 

 a thin bed of agate-like concretions near the base of the formation. 



"In the vicinity of Exeter post-office the shales are separated from the 

 underlying Eed Beds by a well-marked unconformity. The Eed Beds 

 were thrown into gentle undulations and these undulations eroded pre- 

 vious to the deposition of the younger sediments upon them. Several 

 miles west of Exeter post-office the shales rest upon the eroded edges of a 

 local arch, from the top of which about sixty feet of the Red Beds had 

 been removed previous to the deposition of the shales. The gypsum, 

 which is here considered as the top of the Eed Beds, appears in the flanks 

 of the truncated arch. From this point eastward for several miles angu- 

 lar unconformities were noted at the top of the Eed Beds" (Lee, 1902, 5). 



Another section was measured by Lee a few miles east of Exeter post 

 office. The formation is exposed on buttes and mesas in the midst of the 

 canyon. Limestone is an important constituent of the formation at this 

 point. The section is as follows : 



Section near Exeter Post Office, in the Canyon of the Rio Cimarron 



Feet Inches 



Dakota (Purgatoire) . Hard quartzitic sandstone 78 



Shales (Morrison). Shale, arenaceous in places 10 to 15 



Lime concretions 



Red shale 8 



Sandstone 4 



Sandstone and shale (debris covered in places) 50 



Dark red shale 30 



Coarse sandstone 4 



Blue clay 2 



Calcareous clay 2 



Blue clay shale with seams of limestone 30 



Hard brittle limestone 1 



Shale with thin seams of limestone 20 



Shale with impure limestone and sandstone bands and 



irregular masses of agate 10 to 15 



Hard brown, nearly pure limestone 5 



Unexposed 20 



Exeter. White sandstone, massive below but passing to well de- 

 fine layers above 35 



Loose textured and readily weathering sandstone 8 



