NOTE
ON THE
EURYPTERIDÆ
OF THE
DEVONIAN AND CARBONIFEROUS FORMATIONS
OF PENNSYLVANIA.
By James Hall.
In April, 1877, Mr. Charles E. Hall, of the staff of the Second Geological Survey of Pennsylvania, commnnicated to the American Philosophical Society the description of a species of Eurypterus, (E. Pennsylvanicus,) from the Lower Carboniferous rocks of Venango county, and another one from the coal measures of Cannelton, Pennsylvania, under the name of Eurypterus (Dolichopterus) Mansfieldi, from the collection of Hon. I. F. Mansfield. The length of the latter specimen described, without the terminal joint, was two and three-fourths inches.
In April, 1881, Mr. Mansfield communicated to the Philosophical Society "a drawing of a fine fossil Eurypterus, found by him in the shale immediately beneath the Darlington cannel coal bed, lower productive coal messures." This specimen has an entire length of nine inches, of which the telson constitutes about three inches. At a later period Mr. Mansfield placed his collection of these fossils in the hands of Professor Lesley to be described and illustrated in the publications of the Geological Survey. Mr. C. E. Hall
(23 PPP.)
