288 
GEOLOGY OF THE FIRST DISTRICT. 
Red Marl. 
This material is found in many places in the red-sandstone region. It seems to be a variety 
of the sandstone formation, where the materials are so fine as to form a shale, and where 
it contains calcareous matter. It was observed in abundance in the high precipitous banks 
of the Minishecongo creek, in Haverstraw, two miles west of Grassy point, near Capt. De 
Camp’s house. It may be used as a marl, for which it seems well adapted. It is interstra- 
tified with sandstone, shale and grey compact limestone, but gradually crumbles by exposure 
to the weather. 
Compact Grey Limestone. 
Strata of this rock, of a grey or reddish or dove-color, are interstratified with the red sand¬ 
stone, shale and marl. The beds are from one to six or eight feet thick, and some of the 
layers are two feet thick, of perfectly compact homogeneous limestone, which is admirably 
adapted for a building material. It burns to good lime, and some of it would make beautiful 
dove-colored and reddish variegated marbles. Blocks of this stone of a suitable size for sawing 
can be easily procured. 
Red Conglomerate Limestone. 
This rock occurs at or near the junction of the red-sandstone formation with the primitive 
rocks. It is composed mostly of pebbles and angular fragments of grey and black limestone 
(like the adjacent limestone), mixed with pebbles of quartz, granite, gneiss, hornblende, 
sienite, etc., and all cemented together by a reddish argillo-calcareous paste, mixed with 
gravel and sand of the various materials mentioned. Although examination was made to dis¬ 
cover localities where this rock could be wrought as a marble, none could be found which 
did not contain an admixture of some other rocks than limestone. It contains fragments of 
rocks harder than limestone, which would render it difficult to saw and polish. In its general 
aspect it is similar to the Potomac marble. 
These three last rocks, red marl, grey compact limestone, and red calcareous conglo¬ 
merate, are among the last formed rocks of the Red-sandstone division; and they seem to 
be located mostly along the boundary of the formation, and to have been formed of the frag¬ 
ments of its own and the adjacent rocks, ground up more or less by attrition and abrasion. 
Neither the calcareous conglomerate, nor the compact dove-colored and red mottled lime¬ 
stones, were found except in the vicinity of beds of a imestone of more ancient date* than 
the red-sandstone formation, and near the ancient shore on which the attrition may have been 
effected.! 
* This limestone is in many places a metamorphic rock, and would, without examination, be pronounced a primary rock; but 
it is equivalent to the calciferous sandstone of the Taghkanic system, and Formation No. 2 of Prof. Rodgers (the blue or Kitta- 
tinny limestone), the Barnegat limestone, &c. of the Geological Reports. 
t It is yet to be shewn in the proper place, that the strata of the Highland ranges, (a part of which form the ancient shore of 
the Red-sandstone division), were elevated into their present highly inclined position after the deposition of the Taghkanic 
system, but preceding that of the New-Yoric system, and long preceding the red-sandstone era. 
