SHUMARD—GEOLOGY OF N. MEXICO. 277 
softer varieties often pass upwards, almost rete a ~ 
seiner white carbonate of lime, sometimes fifteen 
twenty feet thick. 
As we ee 
diminishes in thickness, and, in oc ap 
's entirely, and is replaced by thick hich: Deilevah-at 
esta an much coarser than —_ pores <r Wear encountered, ad and 
abounding in a great Tanaoue re 
proaching the source of this d he fragments 
not only larger and mo e a i is incre 
ing ger and more angular but the laces, was estimated 
at from four to five hundred feet. ‘ 
_At the distance of Shopabeng miles from the mouth of 
