HILL: GEOLOGY OF THE ISTHMUS OF PANAMA. 247 
Isthmian section are largely developed throughout this region. Тһе 
formations of the River Тауға described by Maack,! are almost identical 
in character with that of Vamos 4 Vamos and lie directly within their 
line of strike, and are much nearer the Caribbean than the Pacific. 
From the mouth of the Atrato eastward to the mouth of the Gulf of 
Maracaibo, and thence in the parallel fringing islands along the northern 
shore of South America, the record of continuity seems quite complete. 
Maack? found the formations around Turbo, near the southern end of the 
east shore of the Gulf of Darien, to consist of clays with coal which he 
thought to belong to the Tertiary period. 
The low chain of hills near Cartagena, according to Hermann Karsten,’ 
aro composed entirely of Tertiary and Quaternary deposits, and they 
contain thiek agglomerated limestone beds alternating with sands and 
marls, containing beds of argillaceous sandstone very much like those of 
the Isthmus of Panama. Karsten also gives many other localities from 
Cartagena eastward. 
Sievers* in his recent map of Venezuela, has shown the continuation 
of the possibly Eocene and “ Miocene” formations east of the Gulf of 
Maracaibo, near the northernmost point of South America, latitude 12°, 
on the mainland and the peculiar peninsula of Paraguana. East of this 
peninsula the east and west coast of the northern end of South America 
drops southward over a degree of latitude, and from Puerto Cabello be- 
comes granitic. The strike of the “ Miocene” formations of Paraguana 
continued eastward is north of the main continental outline, and the 
formation outcrops in the islands of Curagoa and Trinidad. 
The foregoing observations certainly indicate the existence of a con- 
tinuous littoral of older Tertiary sediments around the Caribbean side of 
the Tropical American region, and incidentally a pre-existing land which 
they bordered. Of course it is impossible, from the lack of paleontologic 
evidence, to state that these older Tertiary beds are exactly synchronous, 
but they probably belong to the continuous series of sediments of the 
Eocene and Oligocene epochs. Sapper shows from their position that 
they are Pre-Pliocene in Yucatan and Guatemala. Dr, Dall’s studies of 
my own collection, as given in the Appendix, show that they are Eocene 
and Caribbean Oligocene along the Isthmian and Costa Rican coasts, 
1 Previously cited. 
2 Op. cit., page 160. 
5 Géologie de l'Aneienne Colombie, Boliviarienne, Venezuela, Nouvelle-Grenade 
et Ecuador, 1886, p. 23. 
t Petermann’s Mitteilungen, 1896, Bonn? Vol. XLII. Part 6, p. 125. 
