chap. Yin. Elevation of Patagonia. 197 



place southward, where I landed, was at Port Desire, 

 340 miles distant ; but from the intermediate districts 

 I received, through the kindness of the Officers of the 

 Survey, especially from Lieut. Stokes and Mr. King, 

 many specimens and sketches, quite sufficient to show 

 the general uniformity of the whole line of coast. I 

 may here state, that the whole of Patagonia consists of 

 a tertiary formation, resting on and sometimes sur- 

 rounding hills of porphyry and quartz : the surface is 

 worn into many wide valleys and into level step -formed 

 plains, rising one above another, all capped by irregular 

 beds of gravel, chiefly composed of porphyritic rocks. 

 This gravel formation will be separately described at 

 the end of the chapter. 



My object in giving the following measurements 

 of the plains, as taken by the Officers of the Survey, 

 is, as will hereafter be seen, to show the remarkable 

 equability of the recent elevatory movements. Round 

 the southern parts of Nuevo Gulf, as far as the River 

 Ohupat, (seventy miles southward of San Josef) there 

 appear to be several plains, of which the best defined 

 are here represented. 



No. 15. 

 Section of Step-formed Plains South of Nuevo Gulf. 

 350 ft. An. M. 200-220 An. M. 80 Est. 



\ 









\ 



i 



West. « ■ — ^ East. 



Level of sea. Scale -^ of inch to 100 feet vertical. 



N.B.— An. M. always stands for angular or trigonometrical measurement. 

 Ba. M. „ barometrical measurement. 



Est. „ estimation by the Officers of the Survey. 



The upper plain is here well defined (called Table 

 Hills) ; its edge forms a cliff or line of escarpment 

 many miles in length, projecting over a lower plain. 

 The lowest plain corresponds with that at San Josef 

 with the recent shells on its surface. Between this 



