and Geognosticdl Constitution of' Spain 9.15 



a deposite, filled with marine organic remains, in which calcai'e- 

 ous sand and pebbles occur, pardy in a loose mass, and partly 

 more or less firmly compacted by means of a calcareous cement. 

 Judging from the included petrifactions, among which are beds 

 of oyster-shells, this deposite, on which Cadiz stands, and which, 

 in some places, rises into hillocks and low hills, belongs to the 

 upper tertiary sea-zoater Jbrmation. Probably the tertiary de- 

 posite mentioned by Brongniart as occurring in the neigh- 

 bourhood of Barcelona, belongs to the same deposite. That 

 Jresh-water limestone occurs in Spain has been sufficiently 

 proved by the observations of Baron Von Ferussac. The 

 deposite very much resembles that so generally distributed in 

 Germany, and is found in different parts of Spain, both in 

 the interior and on the coast, and at different heights. The 

 calcareous breccia, generally with a ferruginous basis, which 

 occurs principally in the south-west, where it is widely dis- 

 tributed, belongs to the latest of the antediluvian deposites. 

 It not only incrusts limestone rocks of different formations 

 more or less thickly, but also fills up rents and fissures in 

 them ; thus it abounds among the calcareous rocks of Gibraltar, 

 where it sometimes contains bones of quadrupeds no longer 

 met with there. The formation of this breccia is ascribed 

 to a catastrophe which affected different parts of the coast of 

 the Mediterranean sea. As Professor Hausmann had not 

 an opportunity of travelling in Murcia, he was not able to 

 confirm or reject the accounts of Spanish geologists, who 

 maintain that it contains true volcanic rocks. The occurrence 

 of other rocks, which are conjectured to have come from below, 

 has been noticed in but few places. Characteristic basalt oc- 

 curs in Catalonia. The porphyritic and basaltic looking rocks, 

 extending from Cabo de Gata, and from Avila, on the north 

 side of the Guadarrama range, are still problematical. Hypers- 

 thene-rock has been found by Professor Garcia in the vicinity 

 of Salinas de Poza, in Old Castile, in contact with Jura lime- 

 stone. Professor Hausmann found in the mountains of Jaen, 

 near to variegated marl (containing masses of gypsum, rocks of 

 greenstone. 



Prof. Hausmatm concludes his discourse with some remarks 

 on the more general geological relations of Spain, in which 



s2 



