150 GEOLOGICAL INVESTIGATION. 



There are no fossils of any kind between this last point 

 and the northeast limits of Cliffdale (the estate of Mrs. 

 Andrew Boardman.) Fossiliferous Trenton forms the 

 eastern edge of the limestone ridge from this point, for 

 at least three miles south, and appears again on the farm 

 of Thomas W. Jaycox, about five miles south of Pough- 

 keepsie. It is doubtless continuous throughout the 

 whole range mentioned, though not always recognizable. 

 It also appears in the parallel ridges to the west of Cliff- 

 dale, and further south. 



On the west side of the Hudson, it appears three and 

 and a half miles north of Newburgh, on the east face of 

 the ridgf, and also at a point from four to five miles 

 southwest of that city. 



It remains to make a few brief statements as to the re- 

 cent progress in that part of the work which is more 

 strictly paleontological. 



The development of points of interest as regards the 

 number and character of the fossils in these two lime- 

 stones has much exceeded anything which I could have 

 anticipated when I last addressed you on this subject. 

 No adequate idea could be given of these facts without 

 going into detailed descriptions, which, when completed, 

 would fill a volume. All, that lean say within the re- 

 maining limits of this occasion must necessarily be so 

 general that I fear it will hardly secure much interest in 

 the subject. 



To the various Trenton fossils previously reported 

 here are now to be added Strophomena deltoidea, and 

 an undescribed species of Triples ia. The fossil called 

 Choetetes compacta has been the subject of controversy 

 as to its true character. Some would assign it to the 

 sponges rather than to the corals. A very careful ex- 

 amination of many microscopic sections, however, seems 

 to prove that one or more corals — one a Tetradlum — are 



gTouped under this name. I hope to publish before 



102 



