XAGUA BAY AND ITS ORIGIN. 



91 



The outlet of the valley continued to the deep outer fiord of the gulf of 

 Cazones by way of the depression north of the now closing barrier shown 

 on the map (see figure 10), and in a direct line eastward of the figure 

 where the seacoast sets back 

 and forms a bay into which 

 the Arimao river empties. In- 

 deed, at floods there is a low 

 connection by which small 

 boats can still pass from the 

 bay to the Arimao, which Mr 

 Mathew states was a path of 

 retreat for the pirates of two 

 centuries ago, when the pas- 

 sage appears to have been 

 deeper. This continuation of 

 the Xagua valley was closed 

 and is now occupied, accord- 

 ing to Mr James Fowler, by 

 accumulations of the red Za- 

 pata loams. 



C A /f f B B E A N 



Figure \o.— Xagua Bay. 



There is a closed depression extending from the 

 southeastern end of the bay to the Arimao river and 

 bay. 



From the Zapata submergence the surface of the land in rising per- 

 mitted the waters to break across the plateau at the present outlet of the 



bay, and with the continued elevation the 

 canyon was formed ; but from its depth there 

 is the evidence that the altitude reached 150 

 or 200 feet above the present level — a feature 

 noticed at the outlet of many of the bays 

 and the rivers which everywhere along the 

 coast have cut out just such canyons as that 

 of Xagua before entering the sea. The exca- 

 vation of the outlet of the bay represents the post-Zapata erosion. Here 

 the canj^on is about two miles long, 1,200 feet and more in breadth, with 

 a total depth of nearly 300 feet. 



Figure ii. — Cross-section of Out- 

 let of Xagua Bay. 



Showing the canyon and fiord 

 at the mouth of the bay. Horizon- 

 tal and vertical scale the same. 



YuMURi Rock-basin. 



On the northern side of Pan de Matanzas there is an old baselevel plain, 

 about 400 feet above the sea, having a breadth of some five miles. Out 

 of this plain the Yumuri valley is excavated. The length of the valley 

 is about six miles, with a breadth of about two and a half or three miles. 

 Its depth is about 400 feet. The lower portion of the valley is a plain, 

 showing flooding, as if it had been a recent lake or bay. The upper part 



XIII— Bull. Geol. Soc. Am., Vol. 7, 1895. 



