112 rfALT DEPOSITS. 



masses of native alum, with a conchoidal or imperfectly 

 lamellar fracture. We were led to hope that we shouU 

 find the mine of alum (mina de alun) in the slaty cordil- 

 lera of Maniquarez, and so new a geological phenomenon 

 was calculated to rivet our attention. The priest Juan 

 Gonzales, and the treasurer, Don Manuel Navarete, who 

 had been useful to us from our first arrival on this coast, 

 accompanied us in our little excursion. We disembarked 

 near Cape Caney, and again visited the ancient saltpit 

 (which is converted into a lake by the irruption of the sea), 

 the fine ruins of the castle of Araya, and the calcareous 

 mountain of the Barigon, which, from its steepness on the 

 western side is somewhat difficult of access. Muriatiferous 

 clay mixed with bitumen and lenticular gypsum, and some- 

 times passing to a darkish brown clay, devoid of salt, is a 

 iormation widely spread through this peninsula, in the 

 island of Margareta, and on the opposite continent, near the 

 castle of San Antonio de Cumana. Probably the existence of 

 this formation has contributed to produce those ruptures and 

 rents in the ground, which strike the eye of the geologist 

 when he stands on one of the eminences of the peninsula ot 

 A.raya. The cordillera of this peninsula, composed of mica- 

 slate and clay-slate, is separated on the north from the chain 

 of mountains of the island of Margareta, (which are of a 

 ciinilar composition,) by the channel of Cubagua ; and on the 

 south it is separated from the lofty calcareous chain of the 

 continent, by the gulf of Cariaco. The whole intermediate 

 space appears to have been heretofore filled with muriatife- 

 rous clay ; and no doubt the continual erosions of the ocean- 

 have removed this formation, and converted the plain, first 

 into lakes, then into gulfs, and finally into navigable channels. 

 The account of what has passed in the most modern times at 

 the foot of the castle of Araya, the irruption of the sea into 

 the ancient saltpit, the formation of the laguna de Chacopata, 

 and a lake, four leagues in length, which cuts the island 

 of Margareta nearly into two parts, afford evident proofs 

 of these successive erosions. In the singular configuration 

 of the coasts in the Morro of Chacopata ; in the little 

 islands of the Caribbees, the Lobos and Tunal; in the 

 great island of Coche, and the capes of Carnero and Man- 

 gliers; there still seem to be apparent the remains of an 



