GEOLOGY AND PALEONTOLOGY OF THE CANAL ZONE. 537 



Oligocene — Continued. Feet thick. 



/. About same as (d) 40 



e. About same as (c) 10 



d. Dark, well laminated and very friable shale 35 



c. Light-gray, limy sandstone and sandy limestone beds. 

 Relatively hard and coarse grained. This limestone 

 varies in thickness from 2 to 12 feet, which would seem 

 to indicate a small unconformity along its top. Lo- 

 cally it contains some thin partings of carbonaceous 



shales 2 to 12 



b. Lens of gravel up to 2 feet thick. Partly consolidated 

 with limy cementing material. Oysters plentiful in 

 this gravel. 



a. Dark, well laminated and very friable shale 30 



4. Dark, well laminated and very friable shaly and tufaceous 

 beds. Some of the layers less than an inch thick. 

 Partings show fossil plants and much organic matter. 

 Some of the layers weather brownish from organic 

 matter. Between the more organic and clay-like layers 

 are thin beds of dark-gray, granular to ash-like tufaceous 



material. Fossiliferous. Exposed 150 



(Fault with a downthrow of more than 125 feet on the south 

 side. Considerable shearing and disturbing of the beds 

 for several feet on each side of the contact.) 

 60126-3. Light gray, limy gravel and some tufaceous material, 

 not well bedded and only partly consolidated with 

 limy cementing material . Fossils, particularly oys- 

 ter shells, are plentiful. This bed seems to mark a 



local overlap or small unconformity 40 



2. Dark-gray, bedded limy tuffs and partly consolidated 

 shales. Differs from (5) in having more granular 

 tufaceous material and less of the fine friable shale 

 material. Is very limy, contains some gravel, 



and oyster shells are common 30 



6012a-l. Dark, well laminated, soft, very friable, carbona- 

 ceous shales and dark-gray, granular, loosely ce- 

 mented tuff beds. Typical lower Culebra beds. 

 Fossil plants; marine fossils include Lepidocyclina 

 panamensis ?, Cyclichna, Conus, Pleurotoma (3 spe- 

 cies), Area, Pecten, Callianassa, etc 150 



Section on west side of Gaillard Cut near Las Cascadas, Canal Commission stations 1617 



to 1597. 



Feet thick. 



20. Yellowish to cream colored clays 15 



Oligocene: 



Emperador limestone — 



6019<7~19. Light gray to yellowish gray, somewhat sandy 

 limestone. Massive, but some bedding in upper 

 part. Very fossiliferous: Pecten, Amusium, 

 Stylophora, Clypeaster lanceolatus, Echinolampas 



semiorbis, Lepidocyclina, etc 35 



37149— 19— Bull. 103 2 



