LETTER OF TRANSMITTAL. PPP. vii 



Cretaceous and Tertiary j)lants to another, Devonian plants 

 to a third. Common forms of shells found in great num- 

 bers in some of our strata are recognized by every geolo- 

 gist; but whenever a new or comparatively rare form is dis- 

 covered the specimen is sent to some palaeontologist of ac- 

 knowledged authority at whatever distance he may be from 

 the place where the discovery is made ; nor would an}* ge- 

 ologist 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 palaeontology is shown by the publication of the 

 admirable report on the Coal Flora of Pennsjdvania and 

 the United States by Mr. Lesquereux, who has been occu- 

 pied ten years in its preparation and publication ; * 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 Juni- 

 ata 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 tlie 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 l)efore it can be said that this part of 

 the Geological Survey of Pennsylvania has been accom- 

 plished. A good beginning has certainly been made, but it 



*V()1. Ill, witli thirty new platon, now tHMes au(l a new index, is just is- 

 suing IVoiii the State i)rinlin<; liouse at llarrishiirg. 



