Page:Descriptions of Some New Species of Devonian Fossils.pdf/1

 DESCRIPTIONS OF SOME NEW SPECIES OF DEVONIAN FOSSILS

CLINTON R. STAUFFER University of Minnesota

A study of materials recently collected from the Detroit River series of Michigan and from the Onondaga limestone of Ontario has revealed numerous forms that cannot be identified with known species. Some of these are too fragmentary to be worthy of description, although the genera are easily determined.

The most fruitful source of this material is the Amherstburg beds in the Stony Island Dry Cut. Here great heaps of the rock removed from this part of the river bed are piled high and are rapidly disintegrating under the weathering processes. In 1916 many of the specimens found were thus badly spoiled and each year is continuing the process to ultimate destruction. Grabau and Shimer have described many of these forms, but there still remain a number of fragments that should be found in well enough preserved specimens for description. Attention has been called to some of the more common genera, some of the species of which are described as follows:

Arachnocrinus ignotus n.sp.

This is a medium to small sized species of Arachnocrinus. The calyx is too poorly preserved for description, or is too deeply imbedded in the matrix to be seen, but doubtless it is small.

Arms more or less uniform in size, uniserial, long, and showing frequent bifurcations. These bifurcations are not uniformly spaced on the different arms and one arm does not branch within 555