GEOLOGY OF CHIAPAS, TABASCO AND THE PENIN- 

 SULA OF YUCATAN.^ 



STRATIGRAPHY. 



If one observes the general features of the distribution of the 

 2feolo2fical formations which constitute the states of South- 

 eastern Mexico he soon finds that in the states of Chiapas and 

 Tabasco there are various distinct geological zones ; a very 

 ancient one in the south of Chiapas formed of plutonic rocks 

 and Palaeozoic formations ; another, more modern, in the middle 

 and northern regions made up of Mesozoic and Tertiary forma- 

 tions. At the foot of each of the above mentioned zones 

 Quaternary deposits are found, forming great plains slightly ele- 

 vated above sea level. In the Peninsula of Yucatan there is not 

 such a variety of geological formations. Nearly all that exten- 

 sive region presents a uniform character, which shows that there 

 have not been there so many geological disturbances as in the 

 mountainous regions of Chiapas, and that these deposits were 

 formed under different conditions. In treating of the orography 

 I will speak more in detail of these differences. Yucatan is a 

 part of the earth which has not participated in the dislocations 

 and depressions that the sedimentary deposits, both Palaeozoic 

 as well as Cretaceous and Tertiary, of Chiapas have undergone,, 

 resulting in the development of mountain chains in that state. 

 The strata are almost horizontal or a little inclined in Yucatan, 



' Boletin del Institute Geologico de Mexico, Num. 3, La Geografia Fisica y la 

 Geologia de la Peninsula de Yucatan, Mexico. 1896. Roy. 4", 57 pp., 2 pi. of sec- 

 tions and 3 folded maps. 



The work from which the following translation is taken is divided into five parts,. 

 viz., geology, orography, hydrography, climatology and distribution of the floral 

 zones, and productions. Part I, geology, seems to us deserving of a wider circle of 

 readers than it is liable to obtain in its original form, and hence we have prepared 

 this translation. The accompanying photo-engravings are sketched from Sapper's 

 geological maps, and will serve to indicate the general distribution of the different 

 formations as understood by that authority. 



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