HILL: GEOLOGY OF THE ISTHMUS OF PANAMA. 243 
Carl Sapper? has described a system of pudding-stones, sands, and red 
or yellow clays as the Todos Santos beds. 
The physiographic significance of the early Mesozoic Red Beds has 
never been interpreted, even in the United States, where they are so 
abundant. In general, however, from the shallow water nature of the 
sediments, the scarcity of marine life, and the presence of plants, they 
indicate the coexistence of extensive areas of near-by land. No Jurassic 
rocks are reported from Central America. 
The Cretaceous Strata. — The present area of the Republic of Mexico 
was mostly beneath the sea in Cretaceous times, but, as we shall show in 
the subsequent discussion, it is doubtful if the whole of the country was 
entirely submerged at any one time during this epoch. 
Cretaceous sediments and limestones are found in the Republic of 
Guatemala on the north side of the granitic proto-ranges. As I have 
shown in this paper, there is one small outerop in Costa Rica. From 
Costa Riea westward Cretaceous deposits have not been reported any- 
where in the Isthmian region, nor are they apt to occur at the surface 
until we reach the Andean and Caribbean folds of Northern Colombia 
and Venezuela. Prof. A. Agassiz has mentioned one Cretaceous species 
from the Isthmus.? They are extensively developed in three distinct 
provinces of the South American continont: along the Pacific border, 
near the Caribbean coasts of Colombia and Venezuela, and in Trinidad, 
and south of the Orinoco in Brazil, Cretaceous rocks also outerop in the 
islands of the Greater Antilles, Jamaica, Santo Domingo, and Cuba. 
The Cretaceous formations of the Pacific coast of South America 
lie along the upturned flanks of the Andes, Тһе exact relations and 
limitations in distribution of its faunas have not been thoroughly es- 
tablished or compared with those of the other South American provinces ; 
but from such figures as have been published of its species, we are in- 
clined to believe that it shows the same great dissimilarity to that of 
the eastern lying provinces of Brazil as does the Cretaceous of our own 
North American Pacific coast to that of the Atlantie and Gulf region. 
The Cretaceous of Colombia and Venezuela east of the Magdalena River, 
as has been fragmentarily published by Boussingault, d'Orbieny, and 
Karsten, certainly shows a great dissimilarity in species to that of the 
strictly Andean province. This is a field, however, which needs explora- 
tion by some one familiar with American Cretaceous paleontology. Тһе 
difference between the Brazilian and Andean Cretaceous is even more 
striking. 
1 See footnote 1, p. 239, 2 Loc. cit., page 178, 
