OF SAXTO DOMI?fGO. " ' 11)7 



sandy shales not much altered, but more so than those about Savana Buey or on the 

 Upper Ocoa. . 



The region towards Azua suffers from the same deficiency of rain, as occurs in 

 the western part of the Santiago Yalley, and the nearly bare soil of the ISTumero, 

 with its thin growth of cactus and thorn bushes, fully attests the great influence that 

 moisture exercises over the fertility of the tropics. On reaching the plain, but little 

 raised above the sea level there is a greater proportion of moisture in the soil, though 

 no more in the atmosphere ; and even here a notable difference is to be seen. Larger 

 trees among which the Guayacan or Lignum-vitas is not rare form forests near the 

 coast ; and further inland, although various species of acacia and cactus make up the 

 thickets, their denser growth and more flourishing appearance attest more favorable 

 conditions. , . 



I know the pass west from Maniel only from the report of Mr. Pennell, who 

 represents it as very similar to that of the I^umero, except that the vegetation is more 

 dense owing to its greater proximity to the high mountains and consequent greater 

 rain-fall. He brought in hand specimens of a coarse sandstone and of a red highly 

 metamorphosed shale, both identical with rocks about Maniel. He obtained them 

 near the summit of the pass. 



West of the junction of these roads, and just east of Azua, the coast gravels are 

 somewhat disturbed, being elevated into two or three low hills ; but along the road 

 there is no outcrop of older formations. ISTear the to^vn, however, on the Rio Bia, the 

 same coarse sandstone found near Maniel on the pass, and in Loma de las Tablas crops 

 out in the bed of the stream, -and further up a gray limestone with white calcareous 

 seams forms low flills. Associated with these is a little red jaspery claystone, the 

 whole having a southern dip. ISTorth of the town, and west of the river, the sandstone 

 and limestone are again encountered at Iliguereta. IsTear this placa, and near the 

 upper edge of the gravel is a stream almost always dry called the Agua Hedeondo 

 or stinking water. About its upper part thei'e is a group of little petroleum springs 

 which make their way to the surface through the gravel. The underlying rock is 

 nowhere visible, but the material probabl}^ originates in the Cretaceous shales or 

 sandstones below, and which cannot be very far fi-om the surface. A few little pools 

 occur in the nearly flat ground neai' the arroyo, and the earth and sand in its bed are 

 cemented by the bituminous matter into a compact mass, in the same manner as 

 occurs in a hundred places in California. A few 3^ears ago an attempt was miule to 

 work the deposit. Some pits were sunk now filled with water, on the surface of 

 which there floats a thin scum of viscid oil. Besides these anaitesian AveTl Avas com- 



