410 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [May 8, 



little interruption, passing near Burgos, through Old Castille, the pro- 

 vinces of Soria and Guadalajara to Tamajon and Congostrina in the 

 neighbourhood of the celebrated mines of Hiendelencina, which we 

 have already noticed. A ridge which passes by Segovia, the inclined 

 strata of which rest against the granites of the Guadarrama, must be 

 considered as a continuation of the same formation. The cretaceous 

 beds probably exist more extensively in the centre of Spain, and par- 

 ticularly in the ancient kingdoms of Aragon and Valencia. I only 

 know of a few particular spots, as in the province of Teruel, where 

 they overlie the Jurassic beds. 



The cretaceous formations of central Spain also afford some phse- 

 nomena which deserve the attention of the geologist. The most re- 

 markable is the elevation of great tracts of country to a considerable 

 height without losing their origmal horizontality, as the famous plain 

 or plateau of Baraona, celebrated in the annals of Spanish fairies 

 (Brujas or Witches), between Medinaceli and Almazan in Old Castille. 

 It is nearly 5000 feet (1393 met.) above the level of the present sea. 

 The plateau or table-land of Algora, province of Guadalajara, on the 

 high road from Madrid to Zaragoza, corresponds to the white chalk 

 (craie blanche), and is 4170 feet (1160 met.) above the sea. The 

 village of Penalcazar, in the province of Soria, bordering on that of 

 Zaragoza, is built on a small plateau perfectly horizontal, whilst the 

 neighbouring hills consist of inclined beds of the same formation, and 

 which nevertheless are not so elevated as the plateau itself. At Tama- 

 jon, in the province of Guadalajara, on the other hand, the horizontal 

 portion is lower than the inclined beds. The same phsenomenon, but 

 on a larger scale, occurs in the valley of the Borunda, province of 

 Navarre. 



The great abundance of beds of anthracite (charbon) distributed 

 throughout the cretaceous formations of central Spain also deserves 

 notice. In some respects they are not nearly so important as those 

 of true coal (kouille), but the quality of the fuel is often sufficiently 

 appropriate to be applied to all kinds of industrial purposes. It 

 occurs at Rozas near Reynosa, at a spot not far from Burgos, at seve- 

 ral places in the province of Soria, between the town of that name and 

 Moncayo ; in the Basque provinces, and perhaps also in the Asturias. 

 The great saliferous deposits are also a peculiarity of our cretaceous 

 formations ; the celebrated mine of ('ardona in Catalogna may be men- 

 tioned, as well as Pozo del Rey in the province of Burgos, the salt 

 springs of Anana, province of Alana, which produce more than 50,000 

 fanegas of salt*, &c. 



The formations of the Tertiary period, both the marine and the la- 

 custrine, overlie all kinds of beds of older date ; as, for example, in 

 Catalogna they rest on the chalk, at Valencia on the Jurassic, in Anda- 

 lusia on the transition beds ; in the valley of the Guadalquivir, on the 

 various surrounding beds, and even on granite. The actual configura- 

 tion of the Spanish soil must have been already marked out at the com- 



* A fanega is equivalent to rather more than 99^ litres ; and a fanega of salt 

 weighs about 112 Spanish pounds (51 kilog.). 



