410 NOTES ON THE GEOl.OGY 



water, could they be employed, would absorb the carbonic acid ; 

 and nitric acid, or burning sulphur, the sulphureted hydrogen. 



" The soil on the plain of Oroomiah," continues BIr. Perkins, " is 

 a dark-colored alluvium. Having occasion a few years ago to super- 

 intend the digging of a well on our mission premises, I observed 

 that this alluvium was two and a half feet thick ; and I have observ- 

 ed the same elsewhere, as I have seen the natives digging canals 

 for irrigation on different parts of the plain. In digging our well, we 

 were obliged to go down about sixty feet for water. After passing 

 through the alluvial stratum, we came to drift, consisting of coarse 

 sand, gravel, and pebbles ; the larger stones being of the size of the 

 fist, and many more than twice as large ; the whole much resem- 

 bling the soil on the hill in from of your college (at Amherst) where 

 we labored to form terraces when I was a student there. This 

 drift we found to be eighteen feet thick. We next came upon hard 

 yellow clay, which continued until we reached water; that is, about 

 forty feet. Such I am informed is the usual order and thickness of 

 these deposits." 



" You will be surprised to learn, that our well-diggers penetrated 

 the earth to this depth without the least protection of anything like 

 a curb. They dug the well about three feet in diameter, and en- 

 lai-ged it a little as they descended. They dig in this way at all 

 seasons of the year for the moderate sum of eight to twelve cents 

 per yard." 



In conversation with ]\L\ Perkins, he informs me, that the soil 

 of this remarkable plain is quite similar to that of the prairies of 

 our Western States ; and one of his fellow missionai-ies, who is 

 familiar with our prairies, has remarked, that he had never seen 

 a richer soil, except in one or two places, than that of Oroomiah. 

 Whether the deposits of gravel and clay below the gJluvium is 

 to be regarded as connected with drift, or tertiary strata, we have 

 scarcely materials enough to decide. 



I incline to the belief, that the fertility of this plain depends in 

 a great measure upon the common salt, which probably exists in 

 the soil of that region generally. It is so much diluted by imga- 

 tion, as to prove an admirable manure. A salt desert is an im- 

 age of perfect sterility ; but let fresh water enough be brought 



