Peossek — Hamilton and Chemung Skulks. 



201 



3. Chonetes seiigera, Hall. (r) 



4. Nktoula Gorbuliformis, Hall. (rr) 



5. Sue til a belli 'striata (Con.), Hall. (r) 



6. Nuculites triqueter, Con. (rr) 



7. Leda diversa, Hall. (rr) 



8. Amboccelia umbonata (Con.), Hall. (rr) 



9. JPleurotomaria capillaria, Con. (rr) 



XXV T>\ In the field to the north of the brook and 22 5 feet higher, 

 or 4*20 feet above the river, is a ledge of arenaceous shales and thin sand- 

 stones. The shales are partly thin and even-bedded, similar to the Sherburne, 

 and unfossiliferous, with the exception of a layer possibly one inch thick. 

 The thin layer in which the fossils occur is largely composed of specimens 

 of Spirifer. A few of these are quite large, with the form and conspicuous 

 fine striae of Spirifer mesastrialis, Hall ; but the majority of them approach 

 in form, nearer to Spirifer Tuttius, Hall. These were the only fossils found 

 at this exposure, and, as far as observed, were confined to the one-inch layer. 

 I am inclined to regard them as representing the first of the Ithaca fauna 

 appearing in rocks that are synchronous with the upper part of the Sher- 

 burne formation in the Chenango valley. 



On the river road, one mile south of the point at which the Edson's 

 Corners road joins it, are bluish shales that contain some Hamilton fossils. 

 At this locality these shales are some sixty feet above the Susquehanna river 

 level. The top of the Hamilton is considered to pass beneath the river level 

 in the vicinity of Portland ville. 



XXII E'\ Short gorge in small brook just northwest of Milford Centre, 

 about one and one-quarter miles southwest of Portland ville, or five miles 

 southwest of Milford. In the glen, forty-five feet of shales and thin bluish 

 sandstones are well exposed, and afford a good illustration of the unfossilifer- 

 ous Sherburne rocks of the Susquehanna valley. In some of the blue, 

 arenaceous, thin sandstones are fucoidal markings very similar in shape and 

 general appearance to those figured by Vanuxem and Hall as Fucoides 

 graphica, Van., from the Portage of central and western New York. 



XXII I?. In the brook at the upper bridge and ten feet above the top 

 of the gorge, are bluish, quite fossiliferous, rather arenaceous shales that con- 

 tain the lower Ithaca fauna, Spirifers occurring in several layers. The 

 locality is approximately 200 feet above the Susquehanna river level at 

 Portlaudville, which would indicate a thickness of at least 200 feet for the 

 Sherburne formation in the Susquehanna valley. The fauna is : 



