224 E. Howe— Geology of the Isthmus of Panama. 



Obispo breccias near Empire. The evidence between Culebra 

 and Empire, at Corozal, and in the vicinity of La Boca seems 

 to indicate that an unconformity exists at the top of the Obispo 

 separating it from the Culebra beds. As has been shown, 

 similar unconformable relations appear to exist between the 

 Obispo and Bohio formations on the Atlantic slope. 



Empire limestone. — Hill noted an occurrence of massive, 

 semi crystalline limestone near Empire and from its relations 

 in the held referred it to the Culebra beds.* I am not certain 

 that I identified Hill's exact locality, but I did succeed in find- 

 ing limestone of precisely the same character in the vicinity of 

 the railway station at Empire on both the east and west sides 

 of the track. Fifty feet east of the new station there are 

 exposures, about ten feet thick, of a very massive cream-col- 

 ored limestone in which I was unable to discover fossils ; the 

 outcrop is a small one and its relation to other rocks in the 

 vicinity is not shown. About 150 yards west of this locality 

 on the opposite side of the railway a greenish, impure sandy 

 limestone, hard and compact, occurs beneath thin-bedded cal- 

 careous shales and sandstones, the whole exposure being less 

 than ten* feet thick. Fragments of a Pecten were found in 

 this limestone but no determinable fossils. There are no 

 exposures between these outcrops and the canal cut about one 

 quarter of a mile to the northeast, at which point the Obispo 

 formation is found close to where it disappears beneath the 

 Culebra beds. 



Elsewhere in the Culebra section lenticular bodies of lime- 

 stone, less thick than the massive rock at Empire but other- 

 wise of the same character, are found associated with the cal- 

 careous shales and sandstones, and it seems reasonable, as Hill 

 has suggested, to regard the Empire occurrences as of this 

 nature and belonging to the Culebra beds. The field rela- 

 tions, such as they are, appear to indicate that rocks of the 

 Obispo igneous formation must lie within a few feet of the 

 surface in the neighborhood of Empire, and it is not impossible 

 that the limestone may rest directly upon them. 



About midway between Empire and Las Cascadas on the 

 Panama Kailroad other limestones occur. They are less mas- 

 sive than those at Empire, in places gnarly and crumbling, and 

 being practically at the surface where exposed in the railway 

 cut are considerably weathered. Their color is buff or yellow- 

 ish pink. The few fossils from this locality are poorly pre- 

 served and indeterminable, according to Dr. Dall, but he 

 recognized a nullipore and two species of Peeten and suggests 

 that this may be a reef deposit. 



* Op. cit., p. 195. 



