1 
232 CEMENT MATERIALS AND INDUSTRY. [bull. 
materials that are used in the Lehigh district of Pennsylvania, i 
an argillaceous limestone mixed with a relatively small amount of pu 
limestone. 
Limestones suitable for Portland-cement manufacture occur in sew 
eral different geologic formations. The deposits of argillaceous lime^ 
stone of Trenton age are, however, the principal source of cement 
material, and in view of the great extent of these deposits, it seemi 
probable that the bulk of the New Jersey production will always bfl 
derived from these Trenton rocks. For this reason the distributioj 
and character of the Trenton argillaceous limestones (Lehigh cemen 
rock) of Warren and Sussex counties will be discussed in considerabl 
detail, while the other limestones of the State occurring in the uppe 
Delaware Valley will be described somewhat briefly on a later page 
(p. 240). The shell-marl deposits are also described (p. 242). 
LIMESTONES OF WARREN AND SUSSEX COUNTIES. 
In order that the descriptions of the character, thickness, etc. , o1 < 
the Trenton limestone may be readily comprehended, it will be necessary t 
to pay some attention to the rock formations above and below ititfl 
That part of the geologic column in the New Jersey cement district! 
which is now under discussion contains four formations. These are.| 
reckoning from the top downward: 
d 
1. Hudson shales. 
2. Trenton limestone. 
3. Kittatinny limestone. 
4. Hardyston quartzite. 
In order to understand the respective bearing of these three form 
tions on the cement industry, it is well to recollect that the Trent 
limestone formation furnishes all the u cement rock," while the pur 
limestone used for mixing with the cement rock is obtained parti; 
from the Kittatinny limestone, though the Kittatinny beds are ii 
general highly magnesian. The Hudson shales, though not at pres 
ent used in the cement industry, could well be utilized for mixinj 
with a " cement rock' 1 that is too high in lime. As these three foi 
mations, therefore, are worthy of consideration in connection with th 
cement industry, they will be described separately in some detail 
The Hardyston quartzite, while not directly connected with the cemeru 
industry, is an easily recognized formation whose outcrops usuall' 
limit the Kittatinny limestone belt on the south. 
HARD YS TON Q UAR TZITE.a 
At the base of the great limestone formation of the Kittatinn 
Valley a thin bed of sandstone or quartzite is found at many points 
a These descriptions of the formations are quoted almost verbatim from Doctor Kiimmel's repoi 
previously referred to. 
