OF SA^'TO IXJjMINGO. 



155 



to extend all of the Avay, and describes the little hill of la Gorra as being- a trifling 

 gravel elevation, capped by horizontal sandstone similar to the I'idges between 

 Guaraguano and Hato Viejo. He says this also applies to Loma Jacoba. 



South of Savaneta, almost adjoining the town, the outer or " tirst" eruptive belt is 

 observed covered by the southern margin of the gravels. Going north across the 

 plain to Guayubin, by way of the little hamlet of Martin Garcia, nearly parallel with 

 the Guayubin River, no large outcrops occur, but there are several little exposures 

 in the woods and in one savana just south of the above-named village. The route 

 lies over the beds of the above section, but on top of the gravel there are some small 

 deposits equivalent to those in a similar position on the hill east of the Mao River, 

 and closely resembling them lithologically. In the savana the horse-trail is worn 

 sometimes a foot deep into the ash-gray calcareous claystone, here occasionally 

 seamed with white streaks of earthy lime. Little bluffs of two or three feet high, of 

 the same beds, are also exposed along the margins of dry water-courses, and every- 

 where fossils are so abundant and so beautifully preserved that it is impossible to 

 resist the temptation to dismount every few minutes to pick up some little gem of 

 a • shell too perfect to be left behind, until overflowing pockets warn one to desist. 

 The trifling thickness of the upper pai't of the formation in this region is worthy of 

 note. The gravel-beds are hardly a tenth part as thick as on the Mao, and the 

 underlying yellow shales have suffered a similar if not so great a lo^s. A correspond- 

 ing difference also exists in the height of the Samba Hills, whether caused by a 

 deficiency of material or by a diminution of tlie elevating force. They are barely 

 fifty feet high immediatel}^ adjoining the Guayubin River, though twice that a mile 

 or two east, and they almost entirely disappear ver}^ soon after crossing the rivei'. 

 The horizontal beds continue to their southern base undisturbed, and where the road 

 first reaches rising ground, it climbs a few feet up the face of a sort of bluff, the 

 exposed edges of a nearly horizontal sandstone, full of Oysters and Spondylus. 

 Crossing the hills it is seen that this rock, which doubtless originall}" extended 

 fui'ther south over the plain, and which is the equivalent of the sandstones overlying 

 the gravels elsewhere, is bent into a bi'oad curve, and its northern margin is thinned 

 out and denuded aAvay. I know of no case where it occurs except in the hills directly 

 back of the town of Monte Oristi. Here a coai-se sandstone forms a little tract of 

 rolling ground overlooking the town ; and although I could not connect it along any 

 section with other outcrops, I consider it from its position to be high up in the series 

 and most probably the equivalent of these oyster-beds, which it resembles closely in 

 color and lilholooical character. - • . 



