FOSSILS. 367 



either by elevation or plication. Though, this conclusion may seem monstrous, we believe 

 it to follow legitimately from the premises. Until it is proved that the strata are repeated 

 in some way, we cannot see why this conclusion is not correct. 



Mineral Contents. 



The minerals of the Georgia slate are not numerous. , 



Quartz crystals are occasionally found in these rocks. 



Very distinct crystals of iron pyrites occur in the roofing slates of Rutland County, and are sometimes 

 so numerous in the quarries as to be troublesome. Some excellent specimens of them were obtained from 

 the Eagle Slate quarry in Castleton. 



Octahedral crystals of magnetic oxyd of iron also occur in the roofing slate occasionally. 



lu Castleton, jasper is found in small quantity. In Orwell specimens of calcite were found. 



FOSSILS OF THE GEORGIA SLATE. 



The following species of organic remains have been found in the Georgia slate in Vermont : Barrandia 

 Thompsoni (Hall), B. Vermontana (Hall), Bathynotus holopyga (Hall), Graptolithus Milesi (Hall), the 

 trail of an annelid, and unknown species of fucoids. These were all found in the most northern deposit. 

 Prof. Emmons has obtained several species of fossils from the Georgia slate in New York, to which he has 

 given the following names: Three sea weeds, Buthotrephis rigida, B. flexuosa (Hall), B. asteroides 

 (Fitch); two doubtful species, Palceschorda marina, P. tennis (Fitch); six graptolites, Diplograpsus 

 secalinus (Hall), Monograpsus rectus, Clossograpsus ciliatus, Staurograpsus dichotomies, Nemagrapsus 

 elagans, and N. capillaris; two trilobites, Elliptocephalus asaphoides and Atops punctatus. Emmons in his 

 Manual of Geology, 1860, has figured a Paradoxides trachycephalus, which we suppose to be identical with 

 the Elliptocephalus asaphoidss, and with the Barrandia Thompsoni (Hall). He has also figured an 

 imperfect specimen of Paradoxides quadrispinoms, which we suppose to be identical with the Bathynotus 

 holopyga of Hall. 



Prof. Hall has kindly consented to describe the three species of trilobites and a new graptolite. The 

 descriptions of the trilobites were originally given in the Thirteenth Annual Report of the Regents of the 

 University of the State of New York, 1860. The description of the graptolite is now published and figured 

 for the first time. 



NOTE UPON THE TRILOBITES OF THE SHALES OF THE HUDSON RIVER GROUP 



IN THE TOWN OF GEORGIA, VERMONT. 



BY PKOF. JAMES HALL. 



In the Regents' Twelfth Annual Report on the New York State Cabinet of Natural History, I described 

 three species of trilobites from the shales of the upper part of the Hudson River Group in Georgia, 

 VermoHt. I then referred two of these, with some hesitation, to the genus Olenus (Dalman), and one to 

 Peltura (Milne-Edwards); following the reference to Peltura (Olenus) scarabaioides, as the type. A 

 further examination of these specimens, and some others, has satisfied me of the impropriety of this 

 reference. Although in many respects approaching to Olenus, these forms differ in some important 

 features; and, in order to avoid confusion, they require a distinct designation. In their general aspect, and 

 in some of the details, these fossils bear a resemblance to Paradoxides; from which they are at once 

 distinguished by the less proportional elongation of the body, the smaller number of articulations of the 

 thorax, the direction of the groove or furrow in the lateral segments, and by the form of the glabella. In 

 the first point they also differ from Olenus, which, though having fewer articulations of the thorax, has a 

 larger number than in our fossils. In their general aspect and expression, these fossils are of what might 

 be termed a "primordial type," but yet differ from any of the trilobites in our extreme lower formations, 

 sufficiently to be readily distinguished from them. 



