"Vol. 62.~] THE HIGHEST SILUKIAN OF THE LUDLOW DISTKICT. 199 



bank of the Teme at Ludlow, and in which the entire thickness of the 

 divisions is exposed. The general facies of the fauna is very similar 

 throughout, and there is no very marked difference in lithological 

 character ; but, while ffliynchonella nucula preponderates in the 

 lower beds, Chonetes striatella is the predominant form of the upper 

 member of the group: hence they may be called the Rhyncho- 

 nella-Fl&gs and the Chonetes-Fl&gs. So far as we have been 

 able to determine, they do not vary much in thickness throughout 

 the district. 



The Teme side Group, as its name denotes, is well exposed 

 along the banks of the Teme, both at Ludlow and in the neighbour- 

 hood of Downton Castle ; it comprises beds which are virtually 

 passage-beds into the Old Red Sandstone, and may be subdivided 

 into the Downton-Castle or Yellow Sandstones below, and the 

 Temeside Shales above. The term Downton-Castle Sandstone 

 is used practically in the same sense as Murchison's 'Downton-Castle 

 Building-Stone ' 1 ; while the Temeside Shales include the shales, 

 marls, and grit-bands with Eurypterus and Lingula cornea, which 

 lie between the Yellow Sandstones and the Old Red Sandstone. 



The whole fauna of the Downton-Castle Sandstone, meagre 

 though it be, is more intimately related to that of the Temeside 

 Shales than to that of the beds lying below the Ludlow Bone-Bed. 

 It seems, therefore, advisable to place the beds of this subdivision in 

 the Temeside Group, rather than in the Upper Ludlow Group, with 

 which it has hitherto been classed. The sandstone varies in thick- 

 ness from 30 to 50 feet from place to place, being thickest near 

 Onibury, but everywhere much thinner than we had been led to 

 believe from various papers. 



The Temeside Shales, so far as we have seen, exhibit bat 

 slight variation as regards their thickness, such variation as there 

 is being readily accounted for by the thickening or thinning-out of 

 various grit-bands which occur at different horizons in them. 



Minimum. Maximum. 



Feet. Feet. 



110 Eurypterics-Shales 120 



30 Downton-Castle Sandstones 50 



150 Ckonetes-~Flsigs 160 



110 Rhynchonetta-Fl&gs 120 



40 Dayia-Shales 150 



75 Conchiditm-'Limestone 250 



515 850 



These six major divisions, which constitute six well-defined zones, 

 have been mapped by us throughout the Ludlow district, over an 

 area extending from Ludlow as far south as Overton and Mary- 

 Knowl Dingle, eastward to Caynham Camp, and westward to 

 Downton-on-the-rlock, while our northern boundary runs east and 

 west through Bromfield. 



A small map has also been made of the same beds in the neigh- 

 bourhood of Onibury and Norton, 6 miles north-west of Ludlow 

 (see fig. 8, p. 215). 



1 'Silurian System' 1839, p. 198. 



