Miscellaneous. 429 



places ou the road from New Braunfels to San Antonio, which leads 

 in a south-western direction. Where the road crosses the Cibolo, the 

 limestone forms in the bed of the river singularly shaped rocks, 

 through which the water has eaten its channel, and which are 

 teeming with fossils. At San Antonio the limestone is opened by 

 several stone quarries, and the far-famed Alamo mission has been 

 built of it. West and south of San Antonio, I have not yet seen the 

 limestone myself, but I have reason to believe that it extends much 

 farther in both directions. A specimen of the same Exogyra which 

 abounds on the Guadaloupe was brought to me, and said to have 

 been found among the pebbles in the bed of the Rio Grande. 



Besides this white marly limestone, there is another series of 

 strata to be described. Ascending, from New Braunfels, the range 

 of steep hills which stretches to the north-west of this place, as soon 

 as you leave the level of the valley, horizontal strata of a compact 

 yellowish limestone are seen, resembling very much the compact 

 limestone of Italy, and of Southern Europe in general. Some of the 

 strata are very siliceous, containing large compressed nodules of pure 

 dark- coloured silica. Other beds are so soft that they easily decompose 

 through the action of air. Where limestone is very compact, hardly 

 any trace of fossils is seen in it, but some of the looser strata abound 

 with shells. Among them there is a small species of Exogyra, which 

 from its prominent, spiral beaks and general shape might easily be 

 mistaken for a species of Chama or Diceras ; it is very common, and 

 in some localities occurs in great abundance. Together with this 

 Exogyra, there is in most places a new species of Gryphsea ; also a 

 smooth and globose Terebratula, and occasionally a specimen of 

 Pecten quadricostatus. These beds of soft marly limestone are not 

 only seen everywhere on the mountains in the neighbourhood of New 

 Braunfels, but they extend north of this place about seventy miles 

 as far as to the Piedernales river, everywhere containing the same 

 fossils. Over the same wide range, there are other fossiliferous strata 

 of an entirely different character. I saw them first in a deep ravine 

 near the narrow rock- bound channel of the Guadaloupe, eight miles 

 north of New Braunfels. One thick bed of compact limestone con- 

 tains in immense numbers certain organic bodies of cylindrical shape. 

 These fossils are generally an inch or two in diameter, twisted both 

 ways, and mostly furrowed longitudinally on the surface. At first view 

 I was rather puzzled as to their relations, but on closer inspection of 

 their internal structure, it became evident that they must belong 

 to the order of the Hippurites. that singular division of shells which 

 gives the peculiar fossil character to the cretaceous formation of 

 Southern Europe, from Lisbon in Portugal as far as Asia Minor along 

 the Mediterranean. Some beautiful specimens of a real Hippurites 

 resembling very much a species of Southern France were afterwards 

 met with. In the same beds of limestone with these Hippurites, 

 several species of bivalve shells are found which belong to genera 

 equally characteristic of the Mediterranean cretaceous formations, 

 viz. Diceras and some analogous genera. At last in the same beds 

 also occur a large Pecten of the same section as the Pecten quadricos- 

 tatus, besides several univalves. 



