FOSSIL CRABS OF THE GAY HEAD MIOCENE. 
JOSEPH A. CUSHMAN. 
DuRING the summers of 1903 and 1904 the writer made two 
trips to Gay Head for the purpose of obtaining fossils, espe- 
cially those of the crabs so abundant there. The fossil crabs 
are found in the greensand layer in close relation to the so 
called *osseous conglomerate.' At the northern end of the 
exposure, the crabs occur in a layer about six inches below the 
conglomerate, which is itself at this point a very narrow band. 
In this greensand layer which here is of a very dark, almost 
blackish green color when first dug out, the crabs lie in a natu- 
ral position in the bed. That is, the crabs are in a position with 
their dorsal and ventral surfaces in the plane of the layer which 
contains them. As the edge of the layer is here exposed in the 
cliff and tilted at a very considerable angle, the edges of the 
crabs are struck in digging them out. They occur in very hard 
concretions, often entirely covered or as frequently, with a por- 
tion of the carapace or legs showing at the surface. The shelly 
portions of the crabs are decidedly black in color. The calcare- 
ous matter is still left, however, and entirely dissolves with effer- 
vescence in acid. 
In another portion of the cliff, a short distance north of the 
lighthouse, the crab layer slopes in the opposite direction and is 
of a creamy white color.- The crabs and the material in which 
they are imbedded are in consistency almost like cheese when 
dug out. This material is so soft that it can be easily cut with 
a knife. Upon exposure to the air the material quickly hardens 
usually cracking considerably. The crab 
and shrinks in drying, 
in their details, the small 
remains are here beautifully preserved 
papillae on which the hairs are set being as per 
have been in the living animal. - 
In certain cases in the larger concretions, there are obt 
fect as they could 
ained 
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