64 _ EXPLORATION OF THE COUNTRY BETWEEN 
and of marly clays. No coarse sandstones or beds of conglomerate are 
presented ; and the series would thus appear to have been deposited in 
comparatively quiet water without violent currents. 1 now present a_ 2 
brief description of the specimens collected from the strata as they 
succeed each other upwards from the base of the bluff. 
a. From the base, a thickness of 15 feet exposed to view. 
This specimen is partly in powder and is very friable. Its color is 
white, and when examined with a microscope is seen to consist princi- 
pally of grains of white and translucent or transparent quartz, very 
much rounded and worn, as if by long attrition. They are surrounded 
and cemented together by an opaque white mass which shows fibrous 
crystalizations and resembles a soluble salt which has effloresced by 
exposure to the air. This, however, is not removed by boiling water, 
but dissolves rapidly in clorhydric acid with effervescence, and the 
solution gives a white precipitate with carbonate of ammonia. ee 
white substance, therefore, is ge. of lime. 
b.. 2. Specimen’ from the bottom. 
.ccording to the label it forms thin strata only a 
nating with layers of sand, forming a combined 
n feet. hen treated with acid it effervesces, 
The 
of alumin 
c. 3. Stratum from bottom. 
oose sand; no specimen obtained; thickness about 15 feet. 
d. 4. Stratum from base. 
This is an ash colored powder, consisting in great part of clay; 
silicious grains are also present, and are coarser than those seen int 
specimen from b. The lable with this states that the larger is of very y 
variable thickness, and so soft that it was not possible to obtain a 
coherent lump. I have represented it in the section as three inches in — 
thickness, which you inform me is its proba 
ecimen has a hi ht ash color, and consists, in great part, ne 
: deta op 
nd in this powder several minute but beautiful shells and frag- 
The shells prove on inspection to belong to — 
he 
The first is a land shell, and t 
