234 The Americmi Geologist. April, i9oo 
when tested by optical methods show a variation between labradorite 
and andesine. 
Analysis No. 2 is a phase of the lava on the west side of Katmai 
pass. The structure is porphyritic and the groundmass fine-grained, 
so that the rock is an augite aleutyte. The feldspars, tested by optical 
methods, show labradorite tending to andesine. There is a little 
pale-green augite. The groundmass is microlitic and pilotaxitic, and 
shows flow structure. 
The two analyses agree essentially, the chief difference being that 
No. I contains less silica and more lirrle than No. 2, a fact which is 
at once explained by the much larger proportion of augite in this 
rock. Otherwise the two analyses are very similar and show not 
only a close relation to one another, but in their details bear out the 
results of the optical investigation. 
IDENTIFICATION OF AN OHIO COAL MEASURES 
HORIZON IN NEW MEXICO. 
By C. L. Heeeick and T. A. Bendeat.* 
In 1887 one of us published in \'ol. II of the Bulletins of 
Denison University an annotated list of fossils from the shale 
immediately above the coal at Flint Ridge, east of Newark, 
Ohio. The list was a provisional one and the figures accom- 
panying were crowded upon a few^ plates but the number of 
species is considerable and the list remains, so far as we can 
learn, the last word with reference to this very interesting and 
closely restricted zone. A number of peculiar species were 
found, some of which were described as new while others were 
simply figured. The object was not so much to contribute to 
the descriptive paleontology of the Coal Measures as to illus- 
trate the collocation of forms in a single narrow zone. It is 
believed that a great deal of work of this nature would be use- 
ful even yet. It is not the present intention to discuss the cor- 
rectness of the specific identifications made in the earlier pa- 
per, many of which were provisional, but to call attention to a 
remarkable similarity, one might say almost identity, of forms 
in a similar narrow band of shale found in the Coal ^Measure 
limestone in New Mexico, near Albuquerque. 
A more complete discussion of the Carboniferous forma- 
tions in New Mexico is in preparation but it will serve for our 
♦Geological Survey of the University of New Mexico. 
