190 II. S. WILLIAMS — Till-: CUBOIDES ZONE AND IT- FAUNA. 



i- doI clearly recognized in the sections .smith of New York. In New York 

 the outcrop is losl to the eastward and to the westward, nol bo much by 

 thinning <>nt as by a decrease, until unrecognizable, of the calcareous ele- 

 ments, ami a failure of the peculiar species. In the central pari of its out- 

 crop this Limestone appears at the top of the Hamilton formation, which 

 consists of a series several hundred feel thick of soft shahs, with a few more 

 or Less calcareous zones; and it is followed immediately by a black shale 

 which gradually loses itself by alternate oscillations in a gray, more or Less 

 arenaceous shale and argillaceous sandstone, known in New York as the 

 Genesee shale and the Ithaca group, ami the more sandy portion above as 

 the Portage group. In the region where the Tully Limestone is will devel- 

 oped the black shales contain a fauna corresponding to that <d' the Cardiola 

 retrostriata zone of Europe, ami there is in the sandy Bhales above a fauna 

 rich in < }oniatiU .-• where hest developed. 



At ilm western extreme of the 'Fully lime-tone outcrop in < mtario county 

 lias been seen, far up in the Portage formation, at High Point, a calcareo- 

 silicious /one of about six feet in thickness, containing a rich Brachiopod 

 fauna, which is "particularly interesting, as 1 have 'previously shown Am. 

 Jour. Sc. III. Vol. XXV, p. 97, 1883), on account of its relation to a De- 

 vonian fauna in Iowa, and to faunas, as we shall see Later, in Europe als >. 

 The Ithaca zone also contains some of the species of the Cuboides zone, as 

 we shall see later. 



Above all these comes the typical Chemung fauna of American writers, 

 which i- comparable with Gosselet's Famenien and Condrozien of North 

 Prance ami Belgium. 



For this Btudy the mure importani species in the Tully limestone of New 

 York are the brachiopods. They art — 



Orihia tullierms, Vanuxem. 



Streptorhynchu8 Chemungensis, var. arctostriata, Hall. 

 Strophodonta perplana (var. tulliensis, II. 8. W\), Conrad. 

 Chonetes (Jogani, var.) <nir<>r<i. Hall. 

 Alri/jHi r< Uni/iiris, Linn.. 

 Atrypa aspt m, Schlotheim. 

 Rhynchonella venustula, Sail. 



Spirifer mucrojvxtus 'var. tullien . II . S. W. ■, Conrad. 

 Cyrtina hamiltonensis, Hall. 

 Spirifi r tulliue, I [all. 

 Amboccdia umbonata, Conrad. 



Productella epinulioosta (var. tulliemis, II. B. W. . Hall. 

 Spirifi r fimbriaius, Conrad. 

 Beside these art- species belonging to other orders, a- follows: 



PhaCOpS bufo, ( ' ret ii. 



Dalmaniti i ealliteli -, or l»><>thi, < Sreen. 



