FIELD GEOLOGY. 207 



darker colour, more gritty texture, and in 

 some parts distinctly crystalline. 

 Dip S. 14. 



FOSSILS. 



Fenestella retiformis. Monotis speluncaria. 



Producta horrida. Schizodus obscurus. 



Camarophoria crumena. Bakevellia antiqua. 



Boundaries and Faults. The boundary of the 

 limestone is readily traced by indications here and 

 there, and by rather sudden change of feature; the 

 line runs just S. of Quarry No. 2 ; the shale and pieces 

 of weathered limestone observed there are consequently 

 the last remaining traces of the lower part of the Mag- 

 nesian Limestone. But in walking over the S.E. corner 

 of the sheet it was found to consist of a red or mottled 

 sand ; and in the only open section, the coal-pit shown 

 on the map, the beds were seen to lie in a horizontal 

 position. They must therefore rest unconformably on 

 the limestone which dips S. at a high angle, and the 

 direction of the boundary of the sand when drawn 

 affords a similar indication. For instead of running 

 even approximately parallel to that of the limestone, as 

 it would if the two were conformable, it gradually ap- 

 proaches and would probably overlap it at a short dis- 

 tance farther to the E. 



The line of the sand is next traced in the usual 

 manner, and without difficulty, from the E. side of the 

 sheet nearly to the "W., where it seems to take a sudden 

 and unexpected turn towards the N. Following this 

 new line somewhat dubiously, and with no feature to 



