THE RIO OF YUCATAN. 153 



170 miles, broken only by two narrow passages facing two streamlets — exceptional 

 phenomena on this part of the seaboard. 



The narrow channel separating the mainland from its shifting outer beach 

 is known by various names, such as laguna, pnntano, tierra faugom, but is more 

 commonly called the r/o, or river, or even the Rio Lagartos, " Crocodile River." 

 At first sight this term "river" would «eem to be scarcely justified by a long 

 channel, which during the dry season is interrupted at several points. It is 

 crossed not only by fords, but even by tracks and now by roads and railway 

 embankments, and here and there by a tangle of bushy growths, leaving of the 

 rio nothing but narrow stretches of meres or lagoons. Numerous springs rejppear 

 in the open sea, but the channel itself receives most of the overflow from the 

 underground reservoirs, and the sediment brought down from these sources 

 suffices to maintain the rampart of sands and broken coral reefs by which the 

 marine waters are kept at some distance from the shore. At the north-west 

 corner of Yucatan the fringing sandy cordon curves round southwards with 

 almost geometrical regularity, terminating near a point of the coast known by 

 the name of Desconocida. This double shore-line coincides with that of the 

 marine current, which skirts the beach from east to west, and which here meets 

 a counter- current setting from the coasts of Tabasco and Campeachy under the 

 action of the northern winds At the point where they clash the two marine 

 currents develop a strong whirlpool, by which the shore is eroded. A study of 

 the Yucatan seaboard gives the impression that the peninsula has been gradually 

 formed and continues to increase by these outer strips of s:md, shells, and coral 

 reefs successively added to the m-iinland. 



Climate, Flora, Fauna. 



K& in their relief and hydrographie systems, Chiapas and Yucatan differ also 

 in their climates, though to a less extent, for both regions are comprised within 

 the torrid zone with a temperature approaching the equatorial mean. The 

 Chiapas slope facing the Pacific lies entirely within the play of the alternating 

 monsoons. The north and north-east winds prevail in winter from November to 

 April, while the vendaval, or south wind, that is, the monsoon proper, domiiiates 

 in summer from May to October, when the sun is at the zenith. Nevertheless 

 the normal atmospheric currents are subject to disturbances, by which they are 

 frequently replaced by winds blowing from different points of the coiupass. 

 Both their direction and force are, in fact, endlessly modified by the inequalities 

 of relief, the varying trend and outlines of the rising grounds. As a rule, dry 

 weather and clear skies prevail in winter, while the summer monsoon is accom- 

 panied b}' rains, thunderstorms, and tornadoes. 



Yucatan is mainly exposed to the action of the north-east trade wind, but 

 the almost exclusively limestone formation destitute of surface waters becomes 

 during the hot season a focus of attraction for all the surrounding sea breezes. 

 Stimulated by the intense solar heat dur ng the day, these winds follow the course 



