236 The Atnericaii Geologist. April, 1900 
but the series retains its prevailingly sandy nature in all ex- 
posures seen. There is a considerable fauna, including Belle- 
rophon carbonaria, a Phillipsia, Spirifer camerata and other 
distinctively Carboniferous forms. 
Above this zone is a considerable mass of black carbona- 
ceous limestone and shale not exceeding 150 feet thick. The 
upper portion is usually grey and cherty but may contain car- 
bonaceous and micaceous shales. This series, which is pro- 
vided with a rather homogeneous fauna throughout may be 
taken as the close homologue of the Coal Measure limestones 
of Ohio. Near the top in a number of widely separated ex- 
posures we have found a thin band of very fissile shale "Flint 
Ridge shale," which carries numerous fossils and it is this bed 
that forms the subject of the present paper. 
It might be remarked in passing that Alarcou's statement 
that the limestone of the Sandia range is "mountain limestone" 
is certainly an error for the lowest horizon is distinctively Car- 
boniferous and the uppermost have rather a Permian facies. 
Above the "Flint Ridge" shales is a large series of mas- 
sive grey limestones from 200 to 400 feet thick characterized 
by definite bands of Fu^ulina and Bryozoa. The fauna is ap- 
parently exclusively Carboniferous up to the rather definite 
band of sandstone above the limestone referred to. This Coy- 
ote sandstone marks the beginning of a gradual change in fau- 
na which results in the final introduction of a fauna with dis- 
tinctively Permian elements. Such species as Phillipsia major, 
Meekella striatocostata, Productus punctatus, Terebratula 
bovidens are characteristic of the upper limestone and shale 
series. Above this is an alternation of lime and red sandstone 
until the latter usurps the place entirely and introduces the 
great red bed series of which we shall have occasion to say 
more in another connection. 
When first we found the layer of fissile fossiliferous shale 
above mentioned we were struck by its lithological resem- 
blance to the shales at Flint Ridge, Ohio, in which we had 
worked twelve years ago. It was nevertheless a matter of no lit- 
tle surprise that we should encounter one after another of the 
familiar species with a very slight admixture of dififerent forms. 
Here, for example were the peculiar and easily recognizable 
Crcnipecten fo^rstii. Entolium aviculatum, Lima retifera, Ma- 
