1887.] 44d [Brinton. 



San Rafael. The character of this horizon is thus described by 

 Dr. Flint in a letter to me : 



" Collateral evidence touching man's antiquity here, not less 

 weighty, is found in the neighborhood. The eruptions covering 

 the south-west slope, and the disturbance caused by one, along 

 the ocean beach, elevating the coast range, affords us indisput- 

 able evidence of Pliocene man. In descending the slope through 

 immense ravines formed b}' the annual floods, we see enormous 

 blocks of tufa, isolated by the removal of the material surround- 

 ing them, showing that they had been uplifted by some mighty 

 force and re-embedded in the resultant debris. 



" In 1875-8 and 1883, I spent over a month visiting the coast- 

 hills to the south-west about San Rafael, seeking out the limits 

 of the cataclysm. 



" A strip of land, commencing at Bocano, extends along the 

 coast about forty miles and widens out about San Rafael, termi- 

 nating some eighteen miles above the latter place, at the base of 

 the old primitive range. South-east of the town, a notable break 

 in the upheaval shows that this strip was undisturbed, while the 

 succession of hills to the east and south-east widens out and 

 extends to the south at San Juan del Sur, and thence to Salinas 

 bay. The force culminated against the south-west slope of the 

 old primitive volcanoes mentioned, also shown north-west of San 

 Rafael, where the tufa of the first eruption, on the slip of land 

 mentioned, was unbroken, while in ravines near, the ocean sedi- 

 ment of the upheaval overrides it, forced over it as the rise 

 occurred near b}'^ to the east. 



" This sediment has been carried seaward by the rivers since 

 formed. As they removed the debritus from the tufa, these were 

 found covered with footprints of animals and man. One of these 

 (sandal shod) was forwarded to the Peabody Museum. 



" Where the rivers have cut through the old sea sediment down 

 to the primitive rock, we see beds of shells of many species, 

 among them enormous oysters of an oblong figure, perfect fossils, 

 yet unnamed. They are in situ. Their contents resemble slaked 

 lime. All this shows a sudden elevation. A few can be seen at 

 the National Museum with the fossil leaves in the rock above 

 them, similar to those on the Managua clay under the ash erup- 

 tion. The latter eruption broke up the clay and elevated the 



