No. 50.] 
57 
pressed out of it. It was composed of fine scales, had a yellowish white 
colour, was in small irregular masses, with the appearance of having 
been melted. They were found in the septaria above the Tully lime- 
stone at the above locahty and are supposed by Mr. Vanuxem to be 
new substances.* 
CHAUTAUQUE COUNTY. 
The most interesting object in this county connected with the miner- 
alogical department of the survey, is the carburetted hydrogen gas^ 
which is here evolved in such large quantities. The most remarkable 
localities are those at Fredonia, Westfield and Van Buren Harbor. 
These are commonly called gas springs, and as such, I have particu- 
larly noticed them in my report of 1838. This gas possesses an illu- 
minating power quite equal to that of the purest coal or oil gas, and 
the quantity evolved is moreover so large, that it may in many places 
be advantageously employed. There are also often observed in the 
rock from which this gas issues, thin seams of a highly bituminous 
coal or hardened bitumen. The sandstone sometimes contains cavities 
filled with petroleum. Indeed this rock, especially at the Laona quarry 
has throughout a highly bituminous odour and all the specimens that I 
have tried burn with flame when thrown into the fire ; — from which it 
may be inferred that the whole of this bed is charged with bituminous 
matter.f 
Equally common are springs charged with sulphuretted hydrogen, 
being found in various parts of the county, but especially on the shores 
of Lake Erie. These springs in addition to the sulphuretted hydrogen 
which they evolve, contain minute quantities of the sulphates of lime 
and of magnesia. 
There are here several localities of bog iron ore, but those hitherto 
known are not of much importance in an economical point of view. 
Shell marl is abundant on the banks of Cassadaga lake, where it is 
put up into the form of bricks and burned into lime. Alum and cop- 
* New- York Geological Reports, 1839, p. 283. 
t The following are the results of an analysis of a specimen of the Laona sand- 
stone : — 
Silica, 79.80 
Oxide of iron and alumina, 4.25 
Carbonate of lime, 10.50 
Bituminous matter, 2.10 
Moisture and loss, 3 , 36 
[Assembly, No. 50.] 8 
