ON THE UPPER MISBISSIPPL 505 
lobite, referable, probably, to Spheerexochus, and probably of an undescribed species. 
Three miles above Savannah, Orthis occidentalis, O. testudinaria, Terebratula 
capax, T. modesta, Lepteena sericea, L. alternata, L. deflecta, L. planumbona, and an 
undetermined species of Murchisonia, Streptoplasma, Calymene senaria, and Cheetetes 
lycoperdon. In addition to the above there occur here remains of Orinoidea, refer- 
able to the family Cystidea of Von Buch. The species corresponds with that de- 
scribed in the first volume of the Palzontology of New York, under the name of 
Echino-encrinites anatiformis. The spines of the fossil are tolerably abundant; and 
in a single specimen, the first series of plates (pelvis) still remain attached. 
On approaching Parkhurst, near the boundaries of F. 3, my local sections again 
commence. Five miles above that place, a low ledge of light buff magnesian 
limestone is exposed near the water-level of the river. It contains an abundance 
of casts of columns of Crinoidea. The bodies are rare, but we succeeded in obtain- 
ing two specimens of this portion of the animal. These approach, in the number 
and arrangement of plates, to the genus Hucalypto-crinus, of Goldfuss. 
Two miles further, low ledges of soft, yellowish magnesian limestone appear, 
and continue to prevail as far as Quarry Creek, which joins the Mississippi a short 
distance above Parkhurst. Their height varies from six to twelve feet. A few 
hundred yards above the creek, these strata occur in horizontal beds, elevated five 
feet above the water-level, where a quarry has been opened; and, a short distance 
back from the river, is a second quarry, at a higher level, twenty-six feet above the 
river. The lower layers consist of strata from four inches to a foot in thickness; 
to these succeed thin laminated layers, from a few lines to several inches in thick- 
ness. 
On Quarry Creek, half a mile above the mouth, the strata form perpendicular 
cliffs forty-five feet high. The rock is a soft magnesian limestone,* of a light yellow 
colour, containing small cavities, lined with crystals of quartz and calcareous spar, 
and being easily wrought, is extensively used for the construction of buildings at 
Parkhurst and Le Claire. The beds appear to lie horizontal. 
Between Quarry Creek and Parkhurst, a few exposures of the same beds are seen 
near the water’s edge. They dip at considerable angles, but the inclination is not 
uniform. 
Near the lime-kiln at Parkhurst, where the strata have been laid bare sixteen 
feet above the water-level of the Mississippi, I found a bed filled with casts of poly- 
paria, among which I recognised Stromatopora polymorpha (?), and several other 
forms which I have found in the Upper Silurian strata on Bear Grass Creek, near 
* An analysis of an average specimen from this locality yielded the following proportion of constituents : 
Carbonate of lime, . : : ; ; : : 52-15 
magnesia, ; ‘ ‘ ‘ : ‘ 42-10 
Oxide of iron, alumina, &c., . : ' ‘ : ‘ 1:90 
Insoluble matter, . ‘ ; : . ; , 1-20 
Moisture, . ; . ; ‘ : : é 1-55 
Loss, ‘ ’ ; ‘ : , : . 1-10 
100-00 
