110 TRANSACTIONS OF THE [JAN. 20, 
Occasionally the thinner beds or those less massive are harder 
and sometimes, though rarely,a bed of comparatively hard rock 
is found which answers for building in a region where the rain- 
fall is not great and the chief enemy to durability is the extreme 
range of temperature. The proportion of shale is greater than 
at more northern localities and short sections are similar to those 
obtained in the coal measures of Ohio and western Pennsylva- 
nia, Asin the Rocky Mountain areas, limestone is apparently 
wanting, no bed having been seen. 
The regular dip, the persistence of the sandstones and the ab- 
sence of vegetation make exposures numerous and continuous 
along the cafions. At the same time the entire absence of lime- 
stones and the notable similarity of the sandstones render the 
making of a general section somewhat difficult, for no means is 
available except that of direct tracing, which is often perplexing 
in passing from one canon to another. The sandstones for the 
most part appear to be non-fossiliferous, the only distinct im- 
pression being that of a cypress in a sandstone above the White 
Ash coal bed. The highest sandstone of the section, which, how- 
ever, is evidently far from being the highest bed in the field, 
contains abundance of silicified wood at about half a mile north 
of east from Madrid. 
The coal beds are very numerous, there being nine within 77 
feet below the White Ash seam, but only one of those is more 
than a foot thick, and several of them are not persistent in all of 
the sections. The very considerable thickness of shale and the 
extensive deposits of sandy clay overlying several of the beds 
suggest that the depression after the bed was formed must have 
been gradual and that this area must have been at a consider- 
able distance from the even slightly elevated mainland at the 
north. 
It is unnecessary at this time to give detailed sections, as this 
paper is merely preliminary * and has for its purpose only the 
presentation of such facts as bear upon the condition of certain 
coal beds. The essential features are given in the folllowing 
section, the unimportant coal beds being omitted : 
L.. .Sandstones and siasles 2.9). eee: 2 OS 
2. White Ash coal bed... %: ... escent a6" tov ate 
3. Sandstones, shales and thin coal beds ..... TO? 
ASC OGL 06d, COMING. o's. cis oi) coms here to “2ees 
5. Sandstones, shale and thin coal beds....... 40’ 
G-2Cogt bed. ang Shale feo. a6. «aston: a to >. a 
A sudden illness brought the writer’s studies to an end before the work was fin™ 
ished and the imperfect results are presented only because, as far as they go, they ap- 
pear to possess some interest. 
