Cretaceous and Tertiary plants to another, Devonian plants to a third. Common forms of shells found in great numbers in some of our strata are recognized by every geologist; but whenever a new or comparatively rare form is discovered the specimen is sent to some palaeontologist of acknowledged authority at whatever distance he may be from the place where the discovery is made; nor would any geologist attempt to describe it without reference to museum collections and plates in published memoirs. And the same is true of corals, of fish, of mammals. Mr. Mansfield has had to wait more than seven years to get his Eurypterids properly described and figured as they are in this report.
That the Survey has not been unmindful of its duty in regard to palæontology is shown by the publication of the admirable report on the Coal Flora of Pennsylvania and the United States by Mr. Lesquereux, who has been occupied ten years in its preparation and publication;[1] and by the report on the Permian plants of Greene county and West Virginia, by Prof. Wm. M. Fontaine and Prof. I. C. White. Prof. E. W. Claypole's report on Perry and Juniata counties and the fossils of Middle Pennsylvania, the fruit of three years' field and office work, is now ready to go to press. Prof. Angelo Heilprin, of Philadelphia, has volunteered a report on the Permian shells of Wilkes-Barre. And in the various reports of Prof. Stevenson and Prof. White will be found copious notes of the distribution of fossil forms through the column of rocks in their respective districts.
It must not be supposed, however, that the fossils of Pennsylvania have been adequately studied. In fact, their systematic study has but been begun. The patient field work which Prof. Claypole has expended upon the two counties of Perry and Juniata—or, rather, on parts of these two counties—must be bestowed on the other sixty-five counties of the Slate before it can be said that this part of the Geological Survey of Pennsylvania has been accomplished. A good beginning has certainly been made, but it
- ↑ Vol. III, with thirty new plates, new tables and a new index, is just issuing from the State printing house at Harrisburg.
