224 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 93 



mountain birds as Basileuterus culicivorus culicivorus and Chlorospiiv- 

 gus ophthalmicus ophthalmicus in winter come casually in the heavier 

 forests around Tres Zapotes at only 200 feet above sea level. 



Our exploration of the avifauna of this fascinating region covered 

 only the northern part of the mountain mass of which the Sierra de 

 Tuxtla forms the northwestern bulwark, and that not completely, 

 since we did not collect on the Cerro Prieto, except near its base, or on 

 the Cerro Vigia. To the south of Catemaco there is another group of 

 higher peaks called on some maps the Sierra San Juan and on others 

 the Sierra de Acajucan. These include a Cerro Santa Marta and the 

 steep-sided cone of the Cerro Campanario, which is said to be a little 

 higher than Volcan San Martin. The farther peak, on the side toward 

 Puerto Mexico, is called San Martin de Pa japan and must not be con- 

 fused with the other San Martin covered in this report. This second 

 mountain has at its southeast base the town of Pa japan and is distant 

 only about 40 kilometers from Puerto Mexico. The biological ex- 

 ploration of this part of the region still remains to be made before 

 our knowledge is complete. 



The entire elevated area of the Tuxtlas, lying at the northern end 

 of the great Isthmus of Tehuantepec, is of volcanic nature and is 

 found at the southeastern end of the great arc of extensive recent vol- 

 canic activity that begins in Tepic and extends through Toluca and 

 Orizaba. While available maps may not be wholly accurate in detail, 

 the isolation of the Tuxtla area by extensive lowlands from the pla- 

 teau of central Mexico is easily evident through study of the drainage. 

 The abundant rainfall is carried off by streams that descend the Tuxtla 

 highland on all sides, often with abrupt waterfalls interrupting their 

 upper courses. The San Juan and Papaloapan Rivers flow around 

 it on the west and southwest, reaching the sea at Alvarado, while on 

 the southeast it is bounded by the Rio Coatzacoalcos and its tribu- 

 taries, the waters from which enter the sea at Coatzacoalcos (Puerto 

 Mexico) . To the east is the Gulf of Mexico. 



In modern times the Volcan San Martin has been reported active 

 in 1662 and again in 1793. Of the latter eruption we have a detailed 

 account in a manuscript report made by Jose Mariano Mozifio, a 

 botanist who was in the area at the time. 2 Earth tremors and thun- 

 derous subterranean noises began on March 2, 1793, and continued for 

 two days, with smoke from the volcano. A second, more violent erup- 

 tion came on May 22 and continued at intervals with considerable 



a His notes have been published or reprinted in several places. See Informe de Don 

 Jos6 Mozifio sobre la erupcion del Volcan de San Martin, Tuxtla (Vera Cruz) occurido 

 en el afio de 1793. Bol. Soe. Geogr. Estadistica Rep. Mex., vol. 2, 1870, pp. 62-70 ; and 

 Description del Volcan de Tuxtla por D. Joseph Mariano Mozifio Suarez de Figueroa, 

 botanico naturalista de la Ileal expediciGn de Nueva Espana y de las limites al Norte de 

 California. La Naturaleza, I'eriodico Cient. Soc. Mex. Hist. Nat., vol. 3, 1874, 1875, and 

 1876, pp. 106-114. 



