SAU VINCENTE TO EAGLE PASS. 61 



is an example. Along the line of one of these valleys last mentionei our route led, thus 

 threading our way through the mountain barriers, forming the northern line of the Santa Rosa 

 range, thence emerging on this charming valley a short distance above the town of Santa Rosa. 



The route thence to the Rio Grande at Eagle Pass is over an open country, occupied by low 

 swells of cretaceous limestone, thus merging into that character of country pertaining to the 

 region of central Texas. 



For further details of the lithological character and fossil contents of the various rock ex- 

 posures above alluded to, reference may be had to the lists of Mr. Conrad and Professor Hall. 

 A very interesting paper from the latter gentleman also contains important generalizations, 

 derived from examination of the various geological specimens collected in this and other 

 expeditions. 



The numerous illustrations of scenery from various sources will supply all that can be desired 

 in regard to the general aspect of the region under consideration. 



