946 CARLOS SAPPER 



All these fossils are of the Pliocene ; the formation is equiv- 

 alent to that of Florida. Corals are rare and have not contrib- 

 uted to any great degree to the formation of the rocks. The 

 fossils which I found in Merida have not as yet been deter- 

 mined. 



8. Post- Pliocene or Quaternary limestone, only on the north- 

 ern coast and in the isolated patches in the interior of the pen- 

 insular ; the remainder of the formation in the interior has been 

 destroyed by erosion. It is characterized by Ve?ius cancellata and 

 according to Heilprin, continues northward under the sea. 



B. ERUPTIVE FORMATIONS. 



9. Granite. — Granite forms the greater part of the Sierra 

 Madre of Chiapas ; one reddish variety occurs in the northern 

 part of that mountain chain. This granite seems to be of a later 

 age than the Carboniferous, because the mountain chains com- 

 posed of the limestone of that terrane and of the Santa Rosa 

 beds cease abruptly upon contact with the plutonic rocks of the 

 Sierra Madre. I have been unable to study the conditions at 

 these points on account of the total absence of roads. 



10. Diorite. — Diorite occurs in the northwest part of Chiapas 

 and forms by itself a few mountain chains ; it appears to be of 

 Tertiary Age. 



11. Serpe7itine .— \n "CiXQ x&^xon oi San Francisco Motozintla 

 various dikes of serpentine of a limited area occur between 

 Malpaso and San Isidoro and in the vicinity of Chimalapa. 



12. Andesite. — Andesite eruptions have been found only in 

 the State of Chiapas ; in the northwest, andesitic hypersthene is 

 found forming a mountain chain of considerable altitude (more 

 than 2000 [meters?]), and in the central part of the state 

 hornblendic andesite occurs forming the chains to the north and 

 southwest of San Cristobal, Las Casas and the picturesque chains 

 of Mispilla and San Bartolome de los Llanos, besides many 

 ■dikes of minor importance. These andesites made their erup- 

 tions successively during the Tertiary epoch and before the for- 

 mation of the Neo-tertiaries of Burrero near Istapa and Tene- 



