27 



pense beyond reasonable hope, I fear this groat plain must be left to 

 its pristine solitude and desolation. 



As the department is doubtless familiar with such operations, I will 

 explain briefly the peculiar obstacles we have encountered, the more 

 remarkable from the great depth to wdiich they have pursued us. 



The upper geological formations of this plain consist of what are 

 known to geologists as cretaceous strata^ which here are nothing 

 more than alternations of strata of soft sandstones and variegated 

 marls and clays. In every other part of the world, where these 

 strata have been developed, they are comparatively of small ex- 

 tent, particularly in depth, and with a short departure from the 

 surface of the ground, the sandstones become much harder, and the 

 variegated marls and clays become gradually converted into shales 

 and slates. Almost the precise reverse seems to be the case here, 

 and at a depth of one thousand and fifty feet the strata are softer and 

 crumble more easily than at the surface. We have encountered occa- 

 sional thin seams of flinty limestone, but of too little extent to modify 

 the very peculiar physical character of this formation. 



The first effect of such a geological structure is the necessity of 

 tubing any well to be bored from the very surface, and forcing or try- 

 ing to force the tube to follow the auger closely. This I found is 

 easy enough to do, as I had come prepared for such obstacles, and had 

 plenty of wrought iron tubing and spring or undercutting drills. 

 With the latter we were able, without the least difticulty, to enlarge 

 the bore, below the tube, to any size necessary; but we had not pro- 

 gressed more than six hundred feet with the work, until the friction 

 along the sides of the tube, from top to bottom, resulting from the 

 falling in around of the loose, crumbling strata, absolutely prevented 

 it from moving down, although the bore beloAv was a full inch and a 

 half greater in diameter than the outside of the tubing. I then com- 

 menced to drive, and succeeded, by using great care, in getting it 

 down two hundred feet further. Beyond that depth, the friction be- 

 came so great, that the force necessary to overcome it crushed the 

 wrought iron tube, and stripped off the screw threads at the joints. 



It was impossible to carry the boring below the tube, as the crumb- 

 ling strata of marls and soft sandstones commenced at once to fall in, 

 when unsupported, and filled up the well faster than it could be 

 pumped out. I had, however, anticipated this difficulty, and had 

 brought out tubing of different diameters; and as soon as I found that 

 the large tube could be drawn no further, a smaller one was pressed 

 down inside, and the diameter of the well reduced. 



For a while this obviated the difficulty, but after one hundred and 

 fifty feet the small tube could no longer be forced down, and the 

 strata still continued soft, and fell in constantly. 



By tliese means, and with the severest labor I ever saw, both night 

 and day, exposed on this bleak plain with little protection to an 

 inclement winter, we succeeded in reaching a depth of one thousand 

 and fifty feet; no change whatever has occurred in the strata ; they 

 are as soft and crumbling at the bottom of the well as at the top, and 

 it is impossible to say how much longer they will continue so. 



