HAwortu. | Physical Properties of the Tertiary. 259 
thickness of the Tertiary here is not definitely known, but probably 
is in the neighborhood of 100 feet. 
Southward from these localities along the different tributaries 
of the Smoky the mortar beds are frequently found at the summit 
of the hills. They are as frequently found, however, in interme- 
diate positions, and possibly at or near the base in many instances. 
It is certain, however, that in many cases they are found near the 
uppermost surface of the Tertiary in much greater abundance than 
near the base. Along the Pawnee and its different tributaries well 
developed forms of the mortar beds are frequently found, sometimes 
occupying one horizon, and at other times another. 
Along the Buckner in the southwest part of Hodgeman county 
the sand and gravel are as firmly cemented as at any place known 
to the writer. Here they form a tolerably solid rock which lies at 
the top of the bluffs on the south side of the Buckner. They are in 
beds from 10 to 20 feet thick, varving much more than ordinary sand- 
stone beds do. Below them in this locality the bluffs are composed 
of a looser and finer material. At other places along the Saw Log 
near by the mortar beds are found near the bottom of the Tertiary, 
and not infrequently resting immediately upon the Benton limestone. 
The north bluff-line of the Arkansas river from! some distance 
below Dodge City westward almost to Garden City is protected 
by a well developed mass of mortar beds. Throughout the most of 
this distance three distinct layers of mortar beds can be traced, while 
in other places four or more may be found. They are composed of 
cemented sand and coarse gravel, and are separated from each other 
by beds of clay and fine sand. The weathering processes wear away 
the soft clay beds more rapidly than the mortar beds producing a 
series of narrow terraces along the bluffs similar to those generally 
observed in places where the limestones and shales alternate with 
each other, as is so frequently found in the eastern part of the state. 
South of the Arkansas river but little of the mortar beds ma- 
terial it to be seen until the vicinity of Crooked creek and the Cim- 
arron is reached. Here we have the same lack of regularity so 
noticeable elsewhere. The most pronounced form of the mortar 
beds are often found at the very summit of the bluffs, but by no 
means always so. In other places they occur midway up the bluff, 
