No. 275.] 
317 
turn is irregular and more concretionary, sometimes appearing to be 
merely individual masses of Septaria joined at their edges. It occupies 
nearly the place of a course of Septaria elsewhere occurring in the black 
shale: it doubtless results from an aggregation of a greater or less 
proportion of calcareous matter; so that what in one place becomes a 
few isolated masses of Septaria, in another is a continuous stratum four 
or five feet thick. Above and below this are the usual fossils of the 
upper part of the black shale. This limestone is burned and used for 
hydraulic cement in mill dams, at Big Stream point and elsewhere; and 
is considered better than any obtained from other quarters. Mr. Town- 
shend, of Big Stream point, is now erecting a mill for grinding it after 
burning. The mass is situated in the bank of the lake, where boats 
can approach for loading, and thius the facilities for transportation will 
be great. If it prove equal to the expectations of the proprietor, it will 
supercede much of the material now used as hydraulic cement. 
Between Seneca lake and the east branch of Crooked lake, a high 
ridge or elevated plain slopes gradually to both, being divided trans- 
versely by the ravines and streams. Another elevated table land, varied 
by slight undulations, rises between Seneca lake and the valley of Fiint 
creek, which extends to the head of the w^est branch of Crooked lake; 
this is interrupted by a depression to the northeast of Penn-Yan. Ano- 
ther similar portion, though more irregular, rises between the valleys of 
Flint creek and Canandaigua lake; and the part of the county between 
the two branches of Crooked lake terminates in a high bluff, called Bluff 
point. From near the head of the west branch, extending quite across 
the peninsula, is a valley which appears once to have connected the two 
branches; the highest point is now not more than one hundred feet 
above the lake. The soil of this county ranks among the first in qua- 
lity. 
TOMPKINS. 
The northern portion of this county, between Seneca and Cayuga 
lakes, is underlaid by rocks of the group last described in Seneca coun- 
ty. These, as well as the rocks below the black shale, Tully lime- 
stone, &c. appear in all the deep ravines communicating with the lakes, 
and are finally exhibited at the gorge of Goodwin's falls. This is an 
immense chasm, into w^hich the water descends perpendicularly one hun- 
dred and ninety-three feet, from the bottom of which we see the amphi- 
theatre of rocks rising around us, and by the effect of perspective, clos- 
ing over us three hundred feet above our heads. The black shale visi- 
ble for eighty feet above the Tully limestone, is succeeded by more than 
