TATE — ON THE GEOLOGY OF BEADNELL. 



67 



width and characters are the same throughout the entire length ; it 

 occurs in large rounded loops from half an inch to more than three 

 inches apart. 



Having found sections showing the interior of this curious fossil, I 

 have been able to determine the width of the body, and the distance 

 of the articulations from each other. 



This is the most widely distributed of the carboniferous annelids ; 

 it occurs in sandstones of the mountain-limestone at Beadnell, Scre- 

 merston, Howick, Haltwhistle,* and also in flaggy beds of the millstone- 

 grit at Berlin Carr, between Alnmouth and the Coquet. 



Fig. 1. — Upper surface ; the keel-like centre is that portion of the body not 

 covered with cutI. 



Fig. 2. — Section showing the articulations of the body ; a, intestinal canal ; 

 b, muscular layer and articulations ; c, space occupied by cirri. 



f ■ , 



CRissoPODiA MEDIA (Tate). Plate II. figs. 3, 4. 



Length considerable (upwards of three feet, nine inches) ; usual 

 width about four lines ; some specimens are only three lines, others as 

 much as six lines wide ; thickness three lines ; width of body two 

 lines ; length of cirri one line and a half, twenty of them in the space 

 of one inch ; the width and thickness continue the same throughout 

 the entire length. 



It occurs in irregular loops and long undulations which occasionally 

 cross each other, and is quite distinct from the G. Emhletonia, being 

 much smaller and much thicker in proportion to its size ; the cirri are 

 less crowded and the foldings are more tortuous and irregular. 



It occurs in sandstone at Beadnell, abundantly at North Sunder- 

 land, at Newton-on-the-Moor, and at Howick. 



Fig. 3. — Upper surface. 



Fig. 4. — Section showing the cirri and a cast of the body. 



Nemertites (McLeay). — A Genus which has been described from 

 the Silurian formation ; it is thus defined : — Body very long, linear, 

 slender, of nearly uniform thickness throughout, without distinct 

 articulations. 



* On the Iithing, near Combe Crag. 



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