17s Till- AnicriCilll (rroJtKJiKt. St'pti-nilHT, 1S91 
issiu's uiiiU'i' Ihf I'orri' of its own (•x[);iiisi(»ii and not hy hydrostatic 
pressure. If tliis is really the ease, we must, as said altove. tin 
ticipate a steady falliuti oti' in the rate of diminution until it be- 
comes practically constant and the well hecomes a low-pressure 
source of iras. 
The followin<i" deductions are of great economic importance: 
"The steady decline in pressure from 390-380 lbs. on April 20, 1889 to 
05 lbs. on February 2, 1891, predicts a speedy extinction of the use of 
natural gas at the Cambria Iron Works." 
"'One of the wells at (Jrapeville was recently deepened to reach the 
'Gordon Sand' and a small quantity was found, but not enough to warrant 
any hopefulness of its maintaining the supply. A part of the works at 
Johnstown are yet supplied with natural gas from Grapeville, but it is 
weakening so fast that we supplement it with artificial gases.' " Feb. 
26. 1891. 
Again: 
"At the Cambria Works we are using the Archer oil gas to take the 
place of the natural gas and find this a very good substitute. The Archer 
process consists in vaporizing oil and mixing steam at a very high heat 
with the oil. We have also opened our mines again and are using coal 
in a great manv sections of the works." March 13, 1891. 
Sri-rosED Trenton Fossil Fish. 
During the past few months several notices have appeared of a 
discovery of fish fossils in lower Silurian ( Ordoviciau ) rocks in 
Colorado. At the recent meeting of the American Geological 
Societ}'. 3Ir. AValcott. of the U. 8. Geological Survey, exhibited 
some of these, and gave a few notes on the mode of their occur- 
rence. They are found in a red sandstone, more or less mottled 
witli white, and in a calcareous layer of similar color near Canon 
City, and were first collected by Mr. Stanton two or three years 
ago. The}' consist of a few entire plates and innunu'iable frag- 
ments, mostly white or reiUlish ; and of long and apparently 
articulated columns reminding the observer of crinoidal stems. 
They are referred by Mr. Walcott to various kinds of fish and he 
has named several of them in accordance with this view. Thus 
one of them has received the designation of nolnpti/vhlns .' 
americanus (preoccupied by Leidy manj' years ago ), another that 
of Asferoh'pisF desuhratti. while a third is styled I'nhi rhiiim re 
prisca. 
These statements are of course surprising to the pahentologist. 
