﻿REPORT OF THE DIRECTOR T9IO 3 1 



passage beds between the two. These sandy shales are full of or- 

 ganic remains, partly of the supposed seaweed Sphenothallus 

 lati folium Hall and partly of what appear to be large unde- 

 fined patches of eurypterid integument. In the black shales the 

 eurypterid remains are rarer but their surface sculpture is excel- 

 lently retained, and here their organic associates are C 1 i m a c o - 

 g r a p t u s t y p i c a 1 i s and Triarthrus b e c k i . As a 

 result of imperfect retention of these eurypterids in the rocks where 

 they most abound and their sparseness in the shales which have 

 best preserved them, we are still left in ignorance of the full 

 composition of this assemblage, but it is safe to say genera, species 

 and individuals were abundant at this early period and the evolu- 

 tion of distinctive characters which we have heretofore recognized 

 only in a later period had progressed to so sharp a differentiation, 

 that we are compelled to carry back farther in history, some of the 

 commoner generic designations. These remains in the Frankfort shale 

 are distributed through fully 1500 feet of strata off a northeast- 

 southwest coast line in an area of maximum deposition and it is 

 difficult to conceive that the physical conditions of the habitat 

 of these merostomes were those of an inshore pool; they were 

 rather those of a purely marine basin where sedimentation went on 

 rapidly in an appalachian depression. Hence among our assem- 

 blages of these creatures this occurrence is without parallel in res- 

 pect to long endurance, while in the nature of the habitat it is com- 

 parable to that at Otisville. 



All other occurrences of Siluric eurypterids in New York have 

 been desultory and indicate no intercommunication between the pools 

 or colonies mentioned. 



Monograph of the Devonic Crinoidea. This work is progress- 

 ing and the addition of new material has somewhat broadened its 

 scope and usefulness. Its advancement is necessarily slow because 

 of the inability of its author, Mr Kirk, to give his consecutive 

 attention to it, but the field is being gradually covered fully and 

 the work should result in a useful addition to the paleontology of 

 New York. 



Collections. Considerable collections of fossils have been made 

 in the field, particularly from the Clinton formation of Oneida 

 county, for the purpose of determining the rational position of this 

 formation and fauna in the rock series. Excavations in the Agoni- 

 atite limestone of the Marcellus division have resulted in procuring 

 a ton or so of material illustrating the large goniatites and other 

 cephalopods of that horizon, of which the museum collections stood 

 in need. This work has been done by Mr Hartnagel. Doctor 

 Ruedemann has carried on investigations into the nature and rela- 

 tions of the shale formations of the lower Mohawk and upper Hud- 

 son valleys by extensive collecting throughout this region. 



