SOURCE OP ST. Peter's river. 199 



it has been occasionally found in the conglomerate beds 

 associated with this formation, particularly near Mendip- 

 hills, in England ; if it contains veins of sulphate of ba- 

 rytes at the Huddleston quarry near Sherburn, between 

 Ferrybridge and York ; if it is traversed by veins of sul- 

 phate of barytes near Nottingham, at Bramham Moor, &c. 

 may it not then be asked, whether these considerations do not 

 render it probable that the great lead deposite of the west 

 is in this limestone? and is it notlikely that all that has been 

 worked in an alluvion has been detached from this forma- 

 tion ? These are questions upon which, in the present state of 

 our acquaintance with the western limestone, we must 

 profess ourselves unable to give any decided opinion; but 

 from various circumstances which we need not dwell upon, 

 we should incline to consider the lead ore as probably ex- 

 isting in an older limestone which we think underlays 

 this ; and which may be connected with the mountain or 

 carboniferous limestone of Messrs. Conybeare and Phil- 

 lips, with the metalliferous limestone of other geologists. 



The country becomes more undulated as we draw nearer 

 to the Mississippi ; the ridges are low but somewhat steep, 

 owing to the horizontal stratification of the rocks ; one of 

 their sides very frequently discovers the composition of 

 the hills by a steep break. At other times the country pre- 

 sents the waved appearance of a somewhat ruffled ocean ; it 

 is covered with a short dry grass, the vegetation generally 

 appearing inferior to that of the alluvial country through 

 which we had previously passed. This waved appearance 

 seems to have been caused by the production of valleys sub- 

 sequently formed, and extending from north-east to south- 

 west, all dipping to the latter point ; these are said to con- 

 tinue almost in a straight line to the Mississippi. Our ob- 

 ject being to strike that river at a point further north, our 



