268 The American Geoloy/st. April, 1891 
we have more than one thousand square miles of iron ore deposits in 
this area. 
The investigations in regard to the uses of lignite show that the de- 
posits of east Texas are of better quality than those now in use in 
Europe for most purposes for which bituminous coals are used, and the 
possibility of their use for fuel, for the smelting of the iron ores and 
other industrial purposes. 
In north Texas the results of Prof. Cummins' work have proven very 
important. The much discussed question of Permian-Triassic has prob- 
ably been fully explained by the discovery that we have in Texas, rest- 
ing directly upon the Carboniferous, a series of Permian rocks, which 
in the upper members carry great beds of gypsum, and that only these 
upper members extend north of the Wichita mountains in the Indian 
Territory ; that in Texas the conglomerate corresponding to the Shin- 
arump of the West is found overlying these Upper Permian beds uncon- 
formably ; and that the Red Beds above this correspond to the Red Beds 
of the West and are entirely distinct from those below that horizon. 
The proof here is quite conclusive, as we have not only direct strati- 
graphic, but also the very best paleontologic evidence of the age of all 
these beds. 
Along the eastern edge of the Staked Plains, north of the Brazos 
river, the Triassic strata are overlaid conformably by beds of Tertiary 
age. 
In central Texas, Dr. Comstock, by his second year's field work, fully 
confirms and extends the results of last year as already published. On 
December 3d, 1890, we announced the finding of cassiterite in this 
region by Dr. Comstock. Its mode of occurrence has been very accur- 
ately ascertained and it is reasonable to expect its discovery at any 
point where certain Burnetan rocks are exposed, over a belt extending 
from near Burnet to near Mason. Our samples have come from eastern 
Llano county, and eastern Mason county, and are invariably from quartz 
of the oldest Archaean (Burnetan) system, as defined in the first annual 
report of this survey. 
We have not yet discovered deposits of known workable extent and 
the announcement was made for the purpose of encouraging the neces- 
sary prospecting to fully determine the value of the deposits. 
Large amounts of minerals containing some of the rarer elements 
have been found in this region ; enough for commercial purposes as 
soon as any economic use is found for them. 
In western Texas a detailed study has been made by Prof. Streeru- 
witz of the geology of a portion of El Paso county, including the Quit- 
man. Sierra Blanca, and other mountain ranges. Very much has been 
done toward a clearer understanding of the structure and stratigraphic 
relations of the various granites, porphyries, quartzites. marbles, etc. 
in the Cretaceous of this region, the section develops facts of such 
scientific importance as the absence of the alternating beds, and a 
much greater development of the beds of the Washita division than has 
hitherto been given the entire Cretaceous of central Texas. 
