1835.] Estramadura and the North of Andalusia. 349 



terebratula and echinus , identical with those found in Corsica. 

 According to Deshayes these fossils characterize the second 

 tertiary period, of which there is an example near the Straits 

 of Bonefacio. The limestone beds have a slight inclination, 

 and appear to repose on slate and compact limestone, pene- 

 trated by veins of carbonate of lime. The hills formed of 

 this modern limestone, are separated from the right bank 

 of the Guadalquiver, by an alluvial band, forming a small 

 plain upon which the city of Cordova, with its gardens, is 

 situated. The left bank is formed of a steep wall of gray 

 marl, corresponding with the gray marls which accompany 

 the gypsum of the Paris bason. No organic remains were 

 observed, but it is probable that they do exist. At Badajoz, 

 a small chain of limestone hills crosses the course of the 

 Guadiana, forming a steep escarpment on its bank. On the 

 west of this precipice reddish-gray marls occur, possessing 

 the characters of travertine, and near it are found fresh 

 water fossils. Towards the east, the shell limestone is 

 replaced by alternate layers of dolomite and compact rocks. 

 The dolomite is crystalline, with a yellow colour, sometimes 

 filled with small cavities, and interspersed with rhombohe- 

 dral crystals. The rock itself is not slaty, but is deposited 

 in thick beds, which are separated by thin layers of slaty 

 rocks, which are white, earthy, and contain talc, sometimes 

 becoming compact. Associated with them are crystalline 

 rocks, consisting of felspar and amphibole, and crystals of 

 diallage, resembling euphotide, or the black porphyry of 

 Almaden. Sometimes, also, they contain green mica, 

 pyrites, and chlorite. No dolomite is found among the 

 transition rocks, and hence, M. Le Play conceives that the 

 dolomite formation of Badajoz is an altered state of the 

 lacustrine rocks, and that this modification is connected 

 with the infiltration of masses of euphotide. 



Two specimens of this rock afforded, by analysis, the 

 following constituents : — 



Lime 30-0 - 29*0 



Magnesia 19*2 - 18-4 



Protoxide of iron . . . . 2'6 - 4*3 



Carbonic acid 46*4 - 45*2 



Earthy matter *5 - 2*2 



98-7 - 99-1 



