£. Springer—Burlington Limestone in New Mexico. 99 
No. 3. Dark brown ferruginous sandstone, heavy-bedded 
and hard below, shaly above, ..-.--....-.--.---<- 12 feet. 
No. 2. Very light yellowish shaly clays, with irregular 
flinty masses, without fossils so far as observed,_..>.. 8 feet. 
No. 1. Unexposed slope, covered by debris, probably 
RESET. 20 NGOS Se a ek ee 
os. 7 and 8 are the most important of this section 
paleontologically, and from them almost all the fossils collected 
- were obtained. They are characterized by fragmentary disin- 
tegration, especially No. 7, which is generally found as a soft 
shale, and its fossils arc calcareous. From this bed were ob- 
tained most of the Blastoids, the Agaricocrinus, small Rhodoert- 
nus, Cyathocrinus, Barycrinus. In No. 8, most of the fossils 
are wholly or partially silicified, and the larger species of Pla- 
tycrinus and Actinocrinus seem rather to predominate. With 
these exceptions the crinoids are found irregularly throughout 
the two beds. The color of the rock is not a constant charac- 
ter, but is greatly affected by the proximity of mineral veins. 
In general appearance, and the mode of occurrence of the 
fossils, these two bedsare rather like the upper part of the Keo- 
kuk hmestone as it oceurs at Keokuk. They do not in the 
least resemble the Burlington Limestone in lithological charac- 
ters, but tested by their fossil remains, they belong unques- 
tionably to the Lower Burlington, which is developed here to a 
thickness not attained at any other known locality. 
Aside from the echinoderms, the fauna in general resembles 
more closely that of the Mountain Limestone of Belgium, than 
any other with which I am acquainted. It embraces types 
that have been found in the Kinderhook group, and its repre- 
Sentatives, the Waverly, of Ohio, and the Choteau, of Missouri, 
and in all the formations from these to the Upper Coal-meas- 
ures. in their specific affinities, however, the fossils are un- 
mistakably Lower Carboniferous, the few exceptions being of 
types which have a great stratigraphical range, and are there- 
ore of least weight in determining the equivalency of the | 
Tocks. Nearly all the forms described from the Burlington 
limestone are represented here, if not by identical species, cer- 
tainly by similar types. T 
pods of this locality from descriptions, and by direct compari- 
Son with authentic collections from the Lower and Upper Car- 
_ sting and valuable work in the systematic study of the Car- 
boniferous mollusks of Western America. : 
: he notes here given of the fossils of Lake Valley must be 
_ egarded as only preliminary ; they leave for future publication 
j 
