138 CRETACEOUS ROCKS OF TEXAS. 



ultimately result in an intelligence of the agricultural possibilities of the 

 region that will greatly enhance our prosperity. 



Many specimens of the representative soils have been collected and placed 

 in the hands of the chemical analyist for further study. The chemical anaf- 

 ysis of no soil is undertaken, however, until every mechanical and other 

 method is resorted to in its definition, and no soil is analyzed whose geologic 

 origin and distribution is not first ascertained; because, as has been abund- 

 antly shown, much waste by the promiscuous analysis of soils should not be 

 encouraged. 



Mineral Fertilizers. — The region is especially rich in these, and atten- 

 tion is being devoted to their thorough description. While fertilizers at 

 present may not be needed upon any soil within the area itself, nor used to 

 any great extent in the State, they will ultimately be of great service upon 

 non-calcareous soils, especially in the East Texas region, at an early day, and 

 ultimately become a valuable export material. Among the valuable mineral 

 fertilizers abundant in the region, which in other parts of the world are 

 highly esteemed for their great value in agriculture, and are the source of 

 large revenues both for domestic use and exportation, are greensand or 

 glauconite marls, shell marls, chalk marls, and gypsum marls. In addition 

 to these it is also highly probable that valuable phosphatic marls may be dis- 

 covered, as the exceedingly fossiliferous beds of certain .localities are very 

 propitious for their occurrence, which can only be determined after careful 

 investigation. 



Especial attention is also paid in the final report to the question of marling 

 and mixing of soils, after the soil distribution and classification has been 

 completed. 



The field of agricultural geology in this region, when properly investigated, 

 bids fair to reveal new economic possibilities at present hardly dreamed of, 

 and to render its already fertile soils more available by a proper understanding 

 of their uses and defects, which, together with the abundance of water to be 

 supplied by artesian wells in places to be determined by the survey, will in- 

 crease many fold the country's capacity for productivity and population. 



Water Conditions. — A question of great importance to the Cretaceous 

 region is that of water conditions, and much attention has been given it. 

 The ascertainment, utilization, and improvement of these, instead of being a 

 matter entirely of rainfall, as is usually supposed, is more a question of 

 structural conditions of the rocks which underlie the region. It may strike 

 the reader as a bold proposition to state that a fall of fifteen inches of rain in 

 proper season per annum upon one field may be of more value than a hundred 

 inches upon an adjacent one, if they be of two different formations. One 



