s nl.AF llnl.ll.DAHI. [SEC. ARC. EXP. FRAM 



i- verv fiiiolv granulated all over, the other not so on the glabella. 



. o 



Together with these specimen- we liml the remains of a trilobite of 

 quite another type. \Ve hnve two fragmentarv central portions of the 

 .e|ilialon. which undoubtedly belong loan 1 lln'iuinis sp. (see pi. 4. fig. 4) 

 l.ul it i- mil jMissihle to make any exact determination. The HUrnurns 

 forms is typical of the lowest ordovician in N. America. Only one 

 form. /. <iua<lrdtus MALI., is given from the Potsdam Group. 



Other forms belonging to this younger type of fauna include our 

 >mall fragment of a head of a Licliax sp. 



Si 111:1 further describes the beds thus: 



"On the lop of this light-coloured limestone with its fossil ortho- 

 cerites lie less strongly developed strata of i]imrtz sandstone, alternated 

 with limestones, and on the top of that again a bed of close-grained 

 brown limestone, about KM) feet thick, some of the layers of which are 

 fossiliferous. - 



The fossils in this case are just as fragmentary as in the under- 

 lying limestone. Most commonly we find gastropodes, preserved ,i- 

 casts. 



In some pieces we see very frequently a little slender form with 

 numerous coils (see pi. 4. (ig. (it which cannot easily be separated from 

 varieties of the common Hormotomd </rcilix II ALL. which has a very 

 wide vertical extension within the Ordovician. Another form, winch 

 the specimens before n> greatly resemble, is that described by MALI, and 

 WiinTiKi.n from the Pogonip (Iroup in Nevada. Fnxixph^t conijHictn. 

 As regards other gastropode- we find one incomplete specimen of a 

 Madurect >p. (see pi. 4. fig. S). Some fragments of Irilohites also 

 occur. (Ireat interest will be attached to a quite small, badly preserved 

 pygidium with hollowed outer rim (pi. 4, Hg. 7). It has a (iambrian character 

 and presumably belongs to a />V///////tr/.srif.v or Pti/choj>(tria form. 

 Although these few fo--il remains do not give any particularly good 

 data for the age of this hori/on. yet il suggests that the limestone 

 in reality is only slightly younger than the underlying limestone rich 

 in orthocerites. loth /ones are presumably to be classified in the lowest 

 Ordovician Iraii-ilion lion/on. 



A section of a limestone conglomerate taken from a piece collected 

 above the limestone with orlhoceriles at Victoria Head is shown in 

 pi. IV. lig. 11. 



