46 WARM SPRINGS. 



the bed underneath the clay. Now this clay must 

 be pierced before we can reach the water. That 

 this is the origin of spring-wells, as well as of 

 wells in general, may nearly always be most clearly 

 shown by the local features of the case. But 

 sometimes successful borings for springs are made 

 in plains, and at great distances from the slopes of 

 hills. This can only be explained by supposing 

 that there are channels running under-ground, and 

 that often for several miles. This view is suffi- 

 ciently borne out by the well-known fact, that many 

 small rivers, which disappear in fissured strata, 

 come up again at distant spots. And the exist- 

 ence of subterranean communications, which con- 

 duct the water from places lying at high levels to 

 very considerable distances in the plains, is proved 

 in certain cases by indisputable facts. 



An Artesian well in the town of Tours on the 

 Loire, which brings up the water to the surface 

 from a depth of three hundred and fifty-five feet, 

 threw up, on the 30th of June, 1831, many pieces 

 of plants and shells, mixed with a quantity of 

 fine sand. There were found, among these, thorn- 

 twigs several inches long, fresh stems and roots 

 of bog-plants, seeds of many plants, especially of 

 one that grows abundantly in marshes ; these were 

 in a state of preservation which showed that they 

 had not been lying in water more than three or 

 four months ; and lastly there were the shells of 



