430 Miscellaneous. 



Some Hippurites and several species of the Diceras family were 

 also found on the Piedernales ; so that it seems probable that the 

 strata just described have a very extensive range. 



Having presented the facts observed, I offer a few general conclu- 

 sions from them. At first there cannot be the least doubt that all the 

 strata just described are equivalent to the cretaceous formation of 

 Europe. The identity in the general character of the fossils incon- 

 testably proves it. It is more doubtful to which division of the creta- 

 ceous formation they ought toji)e referred. So much however is cer- 

 tain ci priori, that they do not represent the lowest divisions of the cre- 

 taceous system ; since among the organic remains there are no cha- 

 racteristic fossils of the lower greensand or of the gault. The fossils 

 of the white marly limestone first mentioned indicate an age not older 

 than that of the "chalk marl" of England in the series of the creta- 

 ceous deposits of Europe. We might even be inclined to believe 

 those strata equivalent to the white chalk of Europe, if some of the 

 most characteristic fossils of the chalk among them, especially the 

 Belemnites mucronatus, were not wanting altogether. The system of 

 strata partly consisting of compact siliceous limestone, and contain- 

 ing fossils of the Hippurite order, next described, belong still higher 

 in the European series ; for near New Braunfels they certainly lie 

 above the marly limestone. From some observations however made 

 at other localities, I have reason to believe that the two systems of 

 strata are not everywhere so distinctly separated, and form together 

 a single continuous succession of strata of nearly the same age ; and 

 with regard to the age we can at present only say, that the beds be- 

 long to the upper division of the cretaceous formation. It is inter- 

 esting to compare these cretaceous deposits with the cretaceous strata 

 of New Jersey, Virginia, &c. In the latter regions we find beds of 

 a loose calcareous marl and of ferruginous sand, representing the 

 upper division of the cretaceous formation. In their fossils and also 

 their mineralogical constitution they bear a striking analogy to some 

 deposits of England and Germany. In Texas we have a system of 

 rocks which equally correspond to the upper division of the creta- 

 ceous formation, but of a very different character, and not consisting 

 like those just mentioned of loose unconnected materials, but partly 

 at least a very compact siliceous limestone. By their fossils as well 

 as the composition of the rocks, they are closely allied to the creta- 

 ceous formation as it is developed in the south of Europe along the 

 Mediterranean. 



A new and interesting analogy in the geological constitution of the 

 two continents has thus been ascertained, proving the general simi- 

 larity of physical condition and of the laws of organic life in both 

 hemispheres during the period when the cretaceous strata were ori- 

 ginally deposited. 



Still another observation of a general character remains to be stated 

 respecting these cretaceous deposits. About twenty miles north of 

 Fredericksburg, the new German settlement on the Piedernales river, 

 a rock more than one hundred feet high with nearly perpendicular 

 sides stands out from the ground. This rock, which very probably 

 is identical with that which has been laid down on the maps of 



