THE EURYPTERIDA OF NEW YORK | — TOS 
Connected with this difference in rock is that in the aspect of the fauna. 
While the Eurypterus faunas of Buffalo and Pittsford consist almost en- 
tirely of mature and adolescent individuals, the younger growth stages 
prevail in the Shawangunk grit shales and large individuals are represented 
only by fragments which indicate that they may have been destroyed 
by the more turbulent water conditions farther out. On the other hand, 
the general absence of the earlier growth stages at Buffalo and Pittsford, 
together with the presence of the finer grained rock, intimate that there 
we have the habitat of the mature eurypterids which probably, was the 
somewhat deeper littoral, as in the case of Limulus, while the shale inter- 
calations of the Shawangunk grit are the deposits of the shore pools in 
which the larvae were hatched and where the earliest stages of the 
ontogeny were passed, again as in the living Limulus. _ | 
An interesting analogy between this breeding place of the eurypterids 
in Orange county and that of Limulus rests in the fact that the young 
of Limulus are hatched on sandy tide flats and tide zones and the Shawan- 
gunk grit is a coarse sand deposit of this kind. It seems, therefore, a 
proper conclusion that the Shawangunk grit represents a tidal zone 
deposit Of an encroaching sea or of a delta. 
Omitting for the present the peculiar case of the Eurypterus horizons 
in the Frankfort shale and the Shawangunk grit and returning to the 
more typical Eurypterus facies represented by the waterlimes and shales 
of the Salina formation of western New York, we encounter the venerable 
and still current view that these beds were formed under conditions of much 
abnormal salinity. This view is based on the presence of the salt and gypsum 
2’ 2” grit 10’ grit 
2” shale 3’ shale 
1’ 2” grit 7’ grit 
2” shale 4’ shale 
8’ grit 3 60’ grit (estimated) with occasional 
5" shale very thin layers of shale. As these 
g’ grit 60’ have not been quarried, shale layers 
2” shale have been weathered away at ex- 
4’ grit 7 posures. 
Io” shale 
