544 R. T. CHAMBERLIN 
hydrogen and carbon dioxide are of about equal importance; in sur- 
face flows, carbon dioxide predominates. ‘Though carbon monoxide 
and methane are somewhat variable, the minor gases generally 
increase or decrease with the total volumes. 
TABLE VI 
RocKS OF SEDIMENTARY ORIGIN 
No. of | Sul- 
Order Type of Rock Analy- | phur | CO, CO CH, H, N. | Total 
ses gases 
Shales (non-bituminous) . 3 0.00] 3.72] 0.45| 0.11] 0.97| 0.18] 5.43 
2 | Metamorphosed sediments) 13 SSvAl- auilo Seal. AOS 2.54] sO5) Bouts} 
Sandstones and quartzites| 12 SOI > BeXO)| | gattil| asl git Ole) <(06) 
Among sedimentary rocks, sandstones and quartzites yield less gas 
than shales, while the metamorphic group, comprising both altered 
shales and sandstones, together with modified limestones, take an 
intermediate position, though they surpass shales in hydrogen and 
the sulphur gases. 
TABLE VII 
METEORITES 
No. of | Sul- 
Order Type of Meteorite Analy- | phur | CO, CO CH, H, N. | Total 
: ses gases 
I StOMy eden His emstocnee ue ee 12 4.00] 3.77] 0.24] 0.20] 0.50] 0.09] 8.80 
Without SO, of Orgueil) 12 LOOM BQ eTilns ae 2d ZOWe 250!" 1200] ASO 
2 TPOM Siiiesys ys ates ee Pree se) FOO WZ SISO O2|(2 26/8 so 720 
Neglecting Arva...... : 9 S00|—. a2 et O7 O2))tO7)pe e224 e2ees 
A comparison of the two types of meteorites indicates that carbon 
dioxide is much more important in the gas from stony specimens than 
in that from the metallic bodies, but that iron meteorites yield several 
times as much carbon monoxide and hydrogen as do the stones. 
Sufficient data are not at hand to permit a comparison of the amount 
of marsh-gas from these two types; nitrogen, however, appears to 
come in greater volume from the iron meteorites. 
ANALYSES CLASSIFIED BY THE AGE OF THE ROCKS’ 
In addition to those rocks which could be classed either as Archean 
or Proterozoic, there were others which could only be called pre- 
« In this classification of analyses by the age of the rocks, and in the following one 
based on granularity, only my own analyses have been used. 
