1 62 The Ohio Naturalist. [Vol. II, No. 2, 



NOTES OF TRAVEL IN PORTO RICO. 



Robert F. Griggs. 



B}' its conOguratioii, Porto Rico is divided into two parts very 

 distinct from each other in ahnost every respect and of primary 

 importance in all the affairs of the island. The north side, which 

 comprises about two-thirds of the total area, is kept constantly 

 wet with almost daily rains. On the south it has been known 

 not to rain for a whole year in some places. On the north side 

 grows an abundance of luxuriant, tropical vegetation ; on the 

 south in man}- localities are barren hills covered only with scrub 

 brush. But throughout the island there is great local variation 

 in all the climatic and physical conditions. 



Along most of the north side there stretches a low, coast plain, 

 out of which rise numberless, small, steep hills. This plain, 

 everywhere well watered, is in most places very fertile, but in 

 the vicinit}^ of Vega Baja it becomes a sandy waste. This sand 

 desert is one of the most peculiar places it has ever been my 

 fortune to visit. There is no grass (turf-making grass is almost 

 unknown in the tropics), neither are there large trees. Every- 

 where are low bushes not much more than ten feet tall. The 

 sand beneath them is bare in many places, but is covered in others 

 with various forms of herbage, most of w^hich, instead of being 

 composed of desert forms, as would be expected, is made up of 

 the most typical water-loving plants, among which, Sphagnum 

 (two species) and Utricularia are noteworthy. Imagine, if you 

 can, a sphagnum bog shading into loose sand in a distance of 

 only ten feet with no change in level. The explanation of this 

 peculiar fact is, however, not hard to find. The rainfall is so 

 copious that wherever there is any means of holding it, the 

 hydrophytes take hold and spread, themselves acting as water 

 holders when once started, while in other places the water quickly 

 soaks into the sand and leaves it as dry as ever. 



The plain on which this sand desert is located is .separated in 

 most places from the sea by low hills. It is verj^ level and was 

 probably once covered with water out of which projected many 

 rocky islands — the limestone hills of to-day. These hills are a 

 very characteristic feature of the country. From an incoming 

 vessel they are plainly seen projecting like saw teeth all along the 

 coast ; from an eminence back in the country the}' appear to 

 have no system or regularit}^ whatever, but stick up anywhere 

 sharp and rugged as though shaken out of a dice box onto a 

 board. Further inland they are closer together with no plain 

 between, though in other respects like those of the coast. 

 It is as though they were eroded when the sea stood lower than 

 it does to-day, perhaps very much lower; then the valleys were 



